Franklyn M. Branley was the originator of the Let's-Read-and-Find-Out Science series and the author of close to 150 popular books about scientific topics for young readers of all ages. He was Astronomer Emeritus and former Chairman of the American Museum of Natural History-Hayden Planetarium. True Kelley has illustrated many favorite books for children in her fun-filled watercolor style, including several in the Let's-Read-and-Find-Out Science series. She and the author previously collaborated on What Makes a Magnet? and What the Moon is Like? True Kelley lives in Warner, New Hampshire.