Step one? Don't lend books.
"I never lend a book. To lend a book is to tempt the reader with theft. Books are seldom returned," Manguel says.
"If I want somebody to read a book I would buy the book for that person and give it to that person.
"I believe in Polonius's advice to his son — I've got [Shakespeare's Hamlet] in my library: 'Neither borrower nor lender be'.
Step two: follow your nose.
Manguel says his collection reflects his "cornucopia of interests".
He has thousands of detective novels, but very few spy stories, more Plato than Aristotle, the complete works of Zola, hardly any Maupassant, all of John Hawkes and Cynthia Ozick, but few authors on the New York Times bestseller list.
"I don't feel forced to own any book. I don't feel forced to read something because I'm told it's a classic or because I hear that it's on the bestseller list," he says.
And he rubbishes the notion that you shouldn't judge a book on its cover.
"I let myself be guided by my taste. I'm interested in the title or the cover of a book, or something I've heard about the author," he says.
"I bought a book that I loved that has this irresistible title: Dostoevsky Reads Hegel in Siberia and Bursts into Tears.
"How can you not read a book with that title?"