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The New York Public Library has one of the largest public collections in the world. But, unlike Amazon, it does not have seemingly infinite storage. Every book must earn its place on crowded shelves. Nothing gets there by accident. With millions of books to choose from, the library often gets asked how a book gets on the shelves.

Who makes the decision?

Every book is handpicked by a seasoned corps of 16 selectors and helpers who are the gatekeepers to the library’s circulating collection of nearly 5 million books, 1.7 million e-books and 177,000 audiobooks.

These selectors have, at minimum, a master’s degree in library science and a love of reading. They scour thousands of titles so borrowers don’t have to. From inside a squat, brick building in Long Island City, Queens, they are “fighting for good books,” said Michael Santangelo, the deputy director of collection management.