"Excellent."-Steven Poole, The Wall Street Journal • "Terrific."-Liz Else, New Scientist (Best Popular Science Books of 2025 So Far) • "A brilliant overview of the state of modern cosmology."-Alex O'Connor, alexoconnor.com • "This will expand readers' minds."-Publishers Weekly • One of Smithsonian's Ten Best Science Books of 2025 "An intellectual feast."-Carlo Rovelli • "A must-read."-Sabine Hossenfelder • "Wonderfully broad and open-minded."-Roger Penrose • "Remarkable."-Brian KeatingA thrilling exploration of competing cosmological origin stories, comparing new scientific ideas that upend our very notions of space, time, and reality. By most popular accounts, the universe started with a bang some 13.8 billion years ago. But what happened before the Big Bang? And how do we know it happened at all? Here prominent cosmologist Niayesh Afshordi and science communicator Phil Halper offer a tour of the peculiar possibilities: bouncing and cyclic universes, time loops, creations from nothing, multiverses, black hole births, string theories, and holograms. Along the way, they offer both a call for new physics and a riveting story of scientific debate. Incorporating insights from Afshordi's cutting-edge research and Halper's original interviews with scientists like Stephen Hawking, Roger Penrose, and Alan Guth, Battle of the Big Bang compares these models for the origin of our origins, showing each theory's strengths and weaknesses and explaining new attempts to test these notions. Battle of the Big Bang is a tale of rivalries and intrigue, of clashes of ideas that have raged from Greek antiquity to the present day over whether the universe is eternal or had a beginning, whether it is unique or one of many. But most of all, Afshordi and Halper show that this search is filled with wonder, discovery, and community-all essential for remembering a forgotten cosmic past.