The novel about reading that I recommend to everyone who takes books seriously is Penelope Fitzgerald's The Gate of Angels, which is not about reading but has a quality of attention that is itself a kind of argument about what it means to read carefully.

Fitzgerald wrote her first novel at 60 and published seven in the following fifteen years. Her style is compressed in a way that requires complete attention — the sentences are short but dense, implying more than they state, moving faster than they should. She is one of the writers who made me understand that economy in prose is a form of respect for the reader.

I recommend The Bookshop as a starting point. It is 118 pages. It will take two hours. Those two hours will contain more than novels three times its length.