Augmentation is at the center of Deus Ex: Human Revolution, both its storyline as well as its gameplay. Adam Jensen, left augmented via a near-death experience, is a walking super-soldier - but he'll only be able to switch new augmentations in his system on once he's gained a Praxis Point, either through finding or purchasing Praxis Kits, or by gaining 5000 XP.

Below, you'll find a list of all augmentations in the game, including descriptions, and recommendations as far as their usefulness is concerned.

Social Enhancer (2 Praxis)

Upgrades: N/A

Description: Allows Adam to view level of persuasion and personality profiles in key conversations, and influence people in conversations using pheremones keyed to personality type.

Assessment: The Social Enhancer, or CASIE, is a powerful augmentation which gives you the upper hand during "social battles" by allowing you to view detailed personality breakdowns and your current persuasion success. It will also allow you to analyze whether a person is an alpha, beta, or gamma personality type during conversation - careful analysis will allow you to release pheremones in order to influence that person's opinion, provided you keep track of which personality type they are (keep an eye on the on-screen icons - the one which lights up the most is the right option). Overall, a very useful augmentation best attained early, though it's not necessary; can also be skipped if you want more challenge during conversations.

Radar System (Default)

Upgrades: Radar 2 (1 Praxis)

Description: Tracks humans, robots, Turrets, and Security Cameras on radar, within 25 meters. Upgrade doubles radar radius to 50 meters and does not require visual contact.

Assessment: You'll get the Radar System for free upon first becoming augmented, though at first, its range is slightly limited and you'll need to actually be within visual range of targets in order for them to appear on your radar first. The Radar 2 upgrade makes the radar more useful by increasing its size, but more importantly, doesn't require you see enemies before tracking them. The Radar 2 upgrade is cheap and effective, but can be ignored by those who don't rely on radar or who just want to blast their way through the game.

Infolink (Default)

Upgrades: Cochlear Implant (Default), Subvocal Communications Implant (Default)

Description: Allows for silent and discreet communications with individuals via wireless transmission, beamed directly into the brain.

Assessment: The Infolink comes standard and does not need to be purchased or upgraded. It is invaluable (and inescapable), as it allows you to speak with many of your friends and enemies.

Stealth Enhancer (2 Praxis)

Upgrades: Cones of Vision (1 Praxis), Last Known Location Marker (1 Praxis), Mark & Track 1.0, 2.0 & 3.0 (1 Praxis each)

Description: Allows for detailed information and additional tools for stealthy players to exploit, most of it related to enemy perception.

Assessment: The Stealth Enhancer tree is a bit of a wash. Typically, the upgrades aren't very useful unless you plan to go for a complete stealth play-through. The feedback is nice to have, but some of them, suck as Mark & Track, have too much overlap with Smart Vision and the standard radar to be very useful. The exceptions are the Cones of Vision and Last Known Location Marker, which will allow you to play the game more like Metal Gear Solid or Splinter Cell: Conviction. Otherwise, this branch can be ignored entirely.

Hacking: Capture (Default)

Upgrades: Capture 2, 3, 4 & 5 (1 Praxis each), Camera Domination, Turret Domination, Robot Domination (1 Praxis each)

Description: Allows Jensen to hack into computer terminals and keypad locks, with capture level determining the security level Jensen is able to hack, and the "domination" upgrades determining the level of systems access.

Assessment: Hacking: Capture is by far one of, if not the most useful augmentations in the game. Hacking is a common task you'll need to use frequently, and allows you to open locked doors, hack into computers for information, and eventually reprogram robots and other security measures to your own ends. Additionally, hacking allows access to Datastores within the hacking mini-game, which are an easy source of XP and Credits. Simply put, hacking is crucial and should be prioritised over most other augmentations.

Hacking Analyze Add-on (2 Praxis)

Upgrades: Analyze All Datastores (1 Praxis)

Description: Allows Jensen to view detection odds on nodes not directly connected to captured nodes during hacking, and, when upgraded, to view contents of Datastores during hacking before they are captured.

Assessment: Mostly useless. The basic Analyze level is laughable, as there is virtually no need to ever see detection odds of nodes not directly connected to captured ones, and you'll be able to see the chances of connected nodes just fine. While the Datastore upgrade is useful in assessing risk versus reward of persuing Datastores, all Datastores provide some positive benefit, so there's no reason to be picky. Ignore this tree entirely unless you want the bragging rights of being a master hacker.

Hacking: Fortify (Default)

Upgrades: Fortify 2 & 3 (1 Praxis each)

Description: Allows Jensen to fortify nodes during hacking, boosting their defenses. Upgrades increase the defense bonus by +1 each, up to a maximum of +3 defense.

Assessment: Not great. Unless you do a lot of hacking and make heavy use of fortifying nodes, this can be entirely ignored. Fortifying usually carries a detection chance, and high-level security systems will eat right through your defenses anyway, so there's little reason to use this instead of a few Stop! Worms.

Hacking: Stealth (1 Praxis)

Upgrades: Stealth 2, 3 (1 Praxis each)

Description: Reduces chances of detection while capturing nodes. Each level of the augmentation reduces detection chances by 15%, up to a 45% reduction, with a minimum detection chance of 15% all around.

Assessment: If you plan to be a master hacker, this will be your next choice after Hacking: Capture. Even a few points spent on the stealth upgrades will make hacking substantially easier and increase the number of Datastores you're able to access, as you'll be able to take more diversions without tripping security. If you view hacking as merely functional, needed for the odd door or computer, then you can ignore this tree entirely, but considering how beneficial hacking is, it only makes sense to increase your chances of success.

Sentinel RX Health System (Default)

Upgrades: Cardiovertor Defibrillator, Angiogenesis Protein Thereapy (Default)

Description: Regenerates health when Adam is injured, up to a maximum of 100. Contrary to the upgrade descriptions, Adam will die when your health reaches 0 regardless of how many times it claims to restart his heart.

Assessment: Comes by default, and does exactly what it says on the tin. Note that health regeneration is tied to difficulty level, with the hardest difficulty requiring close to 30 seconds to fully regenerate health back to 100. Despite the fact that your health regenerates, don't neglect using healing items, as they can bring your health to a maximum of 200, useful during difficult encounters.

Sarif Series 8 Energy Converter (Default)

Upgrades: Energy Level Upgrade 1, 2 & 3 (1 Praxis each), Energy Rate Upgrade 1 & 2 (1 Praxis each)

Description: Governs maximum energy capacity and rate of recharge.

Assessment: Although you will always regenerate a single energy cell, ensuring you'll abe able to use a single ability, increasing your total capcity and rate of regeneration can be useful for players who like to use lots of active augmentations, like Smart Vision or the Typhoon. If you're only interested in the occasional use of active augments, you may want to still increase the recharge rate, in order to perform takedowns more quickly; meanwhile, capcity upgrades are useful, as you'll be able to use augments for extended periods without having to rely on recharge items.

Implanted Rebreather (2 Praxis)

Upgrades: Hyper-Oxygenation 1, 2 (1 Praxis each)

Description: Allows Adam to pass through toxic gas with no ill effects. Upgrades increase sprint time by 2.5 seconds each.

Assessment: Spending the 2 Praxis Points on the initial Rebreather upgrade is more than worthwhile. While you'll rarely come into a situation that forces you hike through toxic gas, it will provide resistance to Gas Grenades in combat, and allow you to explore the environment more openly, taking shortcuts as they present themselves. The upgrades are less important. Sprinting can be useful in combat or even in stealth, but it's not a critical ability - if anything, get it later in the game to reduce the time you'll spend traveling from place to place.

Typhoon Explosive System (2 Praxis)

Upgrades: Heavy Damage Variant (1 Praxis each)

Description: Allows Adam to use the Typhoon, for a deadly area-of-effect attack (approximately 10 meter radius). Upgrade deals double damage. Requires Typhoon Ammo to use.

Assessment: The Typhoon is a fantastic, and rather overpowered augmentation. If you're going guns-blazing, it's effectively a "panic button", allowing you to kill large numbers of enemies instantly. Additionally, for stealthy players that don't mind killing, it can make for some extremely effective ambushes, especially when combined with other augmentations. The upgrade makes it even more deadly, allowing you to take down bosses in as little as two shots, as well as powerful robots like the Boxguard. Effectively a take-it-or-leave-it augmentation; get it early and upgrade it ASAP, or don't get it at all.

Cybernetic Arm Prosthesis (Default)

Upgrades: Punch Through Wall, Recoil Compensation 1 & 2, Move/Throw Heavy Objects, Carrying Capacity 1, 2 & 3 (1 Praxis each)

Description: Upgrades Adam's cyber-arms, allowing for a wide variety of new abilities and effects, largely related to arm strength.

Assessment: By far one of the best upgrade trees. Not every upgrade is useful for every player, but abilities like Move/Throw Heavy Objects and Punch Through Wall will allow Adam to not only make improvised weapons, but find alternate paths of entry - or make them. Carrying Capacity does what it says, increasing inventory size by two columns each level; whether you want it depends on how pressed you are for inventory space. Last, recoil compensation is extremely useful for players who want to go all-out violent, making handling certain weapons like the Shotgun and Combat Rifle much easier. Pick up Move/Throw Heavy Objects ASAP, and then grab the other upgrades according to preference.

Aim Stabilizer (2 Praxis)

Upgrades: Aiming Motion Control 2 (1 Praxis)

Description: Improves weapon stability, reducing movement-based accuracy penalties by 50%. Upgrade removes all movement penalties.

Assessment: This is the run-and-gun augmentation, plain and simple. If you want to shoot accurately on the move, this tree is for you, and there's no reason to not fully upgrade it. The one alternative might be stealthy players who rely on the Stun Gun - being able to fire it accurately when moving can be useful when speed is necessary. Otherwise, you can ignore this augmentation entirely.

Smart Vision (2 Praxis)

Upgrades: N/A

Description: Allows Adam to see humans, robots and other threats through walls.

Assessment: Smart Vision is less useful than its name implies, as due to the existence of the Radar System, most players won't have any trouble acquiring threats. That said, it can still give more detailed information than the radar can provide, and it helps to visualize enemy placements and patrols within the level to avoid unnecessary alarms. Can be combined with the Laser Rifle to attack enemies through walls precisely, but opportunities with this tactic are limited, as you'll only find the Laser Rifle in the game's final stretch. Pick this up if you want it, but don't feel like you're missing anything by avoiding it.

Retinal Prosthesis (Default)

Upgrades: Cooldown Timer, Flash Supressant (1 Praxis each)

Description: Displays HUD information, including current health, energy, radar, crosshair, active augmentations, and toolbar (PC version only). Upgrades include immunity to Concussion Grenades/Mines, and a precise timer displaying how long enemies will stay alarmed.

Assessment: You'll get this by default, and of course, the HUD is one of the most important things you have in the game. The upgrades are a different story. If you plan to go on killing sprees, the Cooldown Timer is useless; for stealthy players, though, you can shape your tactics depending on how long enemies will be alarmed for, making it one of the better stealth upgrades. The Flash Suppressant, meanwhile, favors run-and-gun players, but considering that Concussion Grenades and Mines aren't very common, you can probably find something better to spend your Praxis Points on.

Reflex Booster (2 Praxis)

Upgrades: N/A

Description: Allows Adam to perform a takedown on two different people simultaneously.

Assessment: If you rely on takedowns to handle most of your threats, then this augmentation is for you. While it might seem that the Reflex Booster's use is limited due to the fact that enemies don't bunch close together in most cases, stealthy players will want to maximize any possible benefits they have, and taking out two enemies at once can help avoid larger conflicts. Additionally, by luring enemies with gunfire, thrown objects, etc., it's possible to bring several enemies together for a double-takedown or two. If you don't use takedowns much, don't bother with this, but if you do, Reflex Booster is simply a must-have by the game's midway point.

Icarus Landing System (2 Praxis)

Upgrades: N/A

Description: Allows Adam to fall from any height without injury, and perform an area-of-effect stun attack upon landing.

Assessment: The Icarus upgrade is one of the more interesting ones, though the opportunities you'll have to use it are fewer than you'll wish for. There are several points where you'll be able to save lots of time or bypass difficult areas by using this augmentation, and on top of that, jumping off of rooftops can save a lot of travel time. The less obvious benefit, the stun attack, allows for some great tactical advantages - being able to jump from one floor to another and take out the enemies underneath you makes for a great entrance, and when combined with the Typhoon, it is a very deadly combination. Every player will want to get this one at some point in the game, but don't bother early on unless you want to explore every possible nook and cranny.

Dermal Armor (2 Praxis)

Upgrades: Damage Reduction 2 & 3, EMP Shielding (1 Praxis each)

Description: Reduces damage Adam takes from firearms and explosives by 15% per level, up to a 45% reduction. EMP Shielding completely negates all electricity and EMP damage, and its augmentation-disabling effects.

Assessment: While Dermal Armor is a pretty obvious choice for those who see themselves getting their hands dirty, the real use of this upgrade path is EMP Shielding. While there are only a handful of places in the game where EMP Shielding comes in handy, it makes up for it by rendering Adam literally immune to electricity, including EMP Grenades and Mines. Additionally, there are secrets you'll only be able to uncover with EMP Shielding, and several boss fights contain electricity as an environmental hazard. Max out Dermal Armor if you feel you need protection in a straight-up fight, but just about every player should have EMP Shielding by the middle of the game.

Cloaking System (2 Praxis)

Upgrades: Longevity Upgrade 1 & 2 (1 Praxis each)

Description: Renders Adam almost completely invisible at a rate of 3 seconds per Energy Cell. Upgrades increase duration to 5 seconds and 7 seconds per Energy Cell respectively.

Assessment: It's a cloaking upgrade... what else could you want? Whether used for sneak attacks or to ghost one's way through a hostile environment, cloaking is extremely useful all around. It has a high energy consumption, however, so you'll need to save it for when you really need it. Note that enemies will still be able to hear Adam while cloaked, potentially setting off alarms and even becoming hostile, and they will still open fire in Adam's general direction if they're given reason. Additionally, cloaking will let you bypass security systems, including laser grids, with impunity. Last, remember that you can still attack without losing your cloak, so don't be afraid to use it offensively.

Cybernetic Leg Prosthesis (2 Praxis)

Upgrades: Run Silently, Sprint Silencing, Jump/Land Silently, Sprint Enhancement (1 Praxis each)

Description: Increases the height Adam can jump to approximately 3 meters. Upgrades allow Adam to move without making noise when running, and to sprint faster.

Assessment: The basic Jump Enhancement is remarkably useful. There are many places in the game where the extra jump height leads to secret areas, alternate entry paths, and tactical advantages... plus, it's just plain fun to bunny hop around. The Run Silent upgrade and its own sub-upgrades make up an active augmentation, which allows Adam to move at full speed without making noise. However, as crouching also produces no noise, the beneifts of Run Silent aren't as great as they might seem. The Sprint Enhancement is reasonably useful for getting places faster and will let you evade enemies quickly in combat, but is hardly essential either. Overall, get the basic Jump Enhancement ASAP, then grab the others if you feel they'd fit your play-style.