Seymour Simon was born and raised in the Bronx in New York City. He attended highschool at the Bronx School of Science. After graduating from the City College of New York with a degree in animal behavior, he worked as a schoolteacher. In 1963 he was asked by Scholastic Inc. to write an article about the moon in anticipation of the moon landing, and he began writing articles for Scholastic magazines. After writing articles for several years, he wrote his first book, Animals in Field and Laboratory (1968). In 1979 he left teaching to become a full-time author. He has written more than 250 books about science for children, and continues to visit schools to talk about science.