How many books are like that? I remember someone wrote about spending 6000 USD

, I dont want to go that far.
Is it some kind of a manual or fiction stories? May be, something like Tolkien's 'Silmarillion' ?
Are these books independent or they must be read in some order? Are there any books focused more on the psycology: confusion after the transformation, fighting the beast inside etc ?
Thank you in advance.