godan verb (-su), transitive verb
digest a book; thoroughly understand through reading
Implies not just reading but fully comprehending and internalizing the content, often used for difficult or substantial texts.
この哲学書を読みこなすのは難しい。
It's difficult to thoroughly digest this philosophy book.
彼は英語の小説を読みこなせるよう
He became able to read and fully understand English novels.