Scott David Westerfeld is an American writer of young adult fiction, best known as the author of the Uglies and the Leviathan series. Born on May 5, 1963, he has written twenty-five novels, with five for adults and the remaining twenty tailored for young adults.

Westerfeld's most notable works include the Uglies quartet, set in a future where cosmetic surgery is compulsory at age sixteen, and the Leviathan trilogy, a steampunk retelling of World War I. He is also known for the Zeroes trilogy, written with Margo Lanagan and Deborah Biancotti, and the Midnighters trilogy, which explores the lives of five teenagers for whom time freezes every night.

His standalone novels set in contemporary New York include So Yesterday, Peeps, The Last Days, and Afterworlds. Westerfeld has won numerous awards, including the Philip K Dick Special Citation, the Aurealis Award, and the Victorian Premier’s Award. His books have been named NY Times Notable Books and BBYA Top Ten Children’s Books of the Year.

In addition to his novels, Westerfeld has contributed nonfiction to Nerve, BookForum, and the scientific journal Nature. He has also worked as a ghostwriter, a factory worker, a substitute teacher, a textbook editor, and a software designer.

Westerfeld currently resides between New York City and Sydney, Australia, with his wife, writer Justine Larbalestier.