To be possessed by a book by no means means to have possession of it. Not only because one may be possessed by books one doesn’t own (library books, borrowed books, illicitly downloaded pdfs), nor even because the books one buys one tends to not read, and the books one has read tend to end up in a charity shop, but because the books that settle in you (and therefore unsettle you) are ones that cannot be possessed. Ones that escape the greedy clasp of your understanding them.
Thoughts fallen by the wayside 