Gravity dominates the universe: It holds the Earth, the Sun, and the Milky Way together, and it keeps our feet firmly planted on the surface of our planet. When an object goes up, it is pulled back to Earth by gravity. These facts make it easy to conclude that gravity is a strong force, but it is actually a very weak force whose confusing and contradictory nature has stumped many investigators. An independent critic from Chapel Hill, N.C., Phillip Mannning’s book Gravity is part of the Chelsea House series called Science Foundations. “Before I started this project, which took about three months, I figured that any book in which the central characters are Galileo, Newton, and Einstein would be a fun undertaking,” Manning said. “As it turns out, I was right. It was a pleasure to watch the modern theory of gravity unfold as each of these great scientists probed the question: Why do things move?”