Can you keep the books from the Secret Library Quest?

Question

I noticed that the books from the Library quest are dropped by bosses and was wondering if you get to keep them or you have to turn them in to progress as well as if you can get multiples of them. Books from the secret library quest Include  ~ The True Book of death  ~ Sinister Book ~ Ornate Tome  ~ Ominous Book ~ Knowledgeable Book 

I ask because I was thinking of making a book collection and was wondering how expensive or rare these might be to get since they are not on market or if I can just ask a friend to go loot me some.

Answer 1

I have all of them, just for collection :) but i think that someday they will have some aplication. And you can check prizes in market. I think one cost like 500k+/-.

Answer 2

Books are not needed to perform the task afterwards. Something like a book from Oberon. I often see this  on floor, others  they are nicer so no one throws them away. It seems to me that the "ornate tome" is expensive, Idk how the rest.

* edit checked prices on Antica. sell 420k buy 36k / sell 450k buy 93k / sell 270k buy 105k. You can't buy on market The True Book of death and Ornate Tome. People sell Ornate Tome on Trade forum.