How Must-Read 50 works

The three ways in

• Critics' pick: won or was shortlisted for a major prize (Pulitzer, Booker, National Book Award, Women's Prize, Hugo, Nebula and more), or chosen for a best-books list by critics, authors and editors (TIME, Modern Library, the New York Times, the Guardian, the Bokklubben World Library).
• Lifetime bestseller: a #1 New York Times bestseller since 1931, one of the ten best-selling books of its year (Publishers Weekly, since 1900), one of the best-selling books of all time, 26 weeks or more on the New York Times lists, a readership of 500,000 or more, or a favorite in a national reader vote (PBS's Great American Read, the BBC's Big Read, Le Monde's 100 Books of the Century).
• Buzzing now: four months or more on the New York Times bestseller lists in the last two years.

Loved by readers

Every book needs at least 10,000 readers (3,000 if it's under two years old) and an average rating of 3.7★ or better (3.5★ for the strongest critics' picks). A rating from only a handful of readers counts for less until more readers weigh in, so one or two ratings can't decide a book.

Readers are compared within each era (new: the last five years; modern: 1990 on; classic: before 1990). New books are rated mostly by fans who chose them, and classics by everyone who was assigned them, so this lets a beloved classic compete fairly with this year's hit.

The fine print

• The Top 50 has at least 10 new, 10 modern and 10 classic books, and no more than 20 nonfiction.
• A series appears once, as its first book, credited with the whole series' prizes and bestseller record. Mystery and thriller series, which read in any order, and multi-volume nonfiction keep each book separate.
• A book less than two years old only reaches the top 10 if it has barely left the bestseller lists all year.
• Books just below our bar sit on a reserve shelf. They never make the Top 50, but they fill out your 50 if you've read most of the ranking.
• Recent books whose main purpose is advocacy on an active political dispute are left out of the Top 50; you can switch them on in your own 50. The rule applies in every direction.
• Everything is re-checked every month: new bestsellers, new prizes and fresh reader numbers.

Tuned to you

• We learn how you rate books compared with other readers, which authors you love, and which kinds of books you lean toward. Your taste can move a book up or down, but only so far, so quality always leads.
• Books on your Want to Read get a small boost. Anything you've read, are reading, or gave up on is never shown.
• Use the slider to lean toward new or classic books.

Where the data comes from

Prizes and best-books lists come from the prizes' and publishers' own records, and bestseller history from the New York Times and Publishers Weekly. Reader numbers come from Hardcover and other large reading communities. We use them to score books; we don't show star ratings, only our own Must-Read Score. Covers, editions and publication years come from Open Library, the Internet Archive's free public catalog.