This book summarizes the evidence for dark matter and what we can learn about its particle nature using cosmic gamma rays. Reviewing results from recent experiments including anomalies that some have attributed to dark matter, this book also discusses how our observations complement other dark matter searches and prospects for future experiments.

It has almost been 100 years since Fritz Zwicky first detected hints that most of the matter in the universe doesn’t directly emit or reflect light. Since then, the observational evidence for dark matter has continued to grow. Dark matter may be a new kind of particle that is governed by physics beyond our Standard Model of particle physics. In many models, dark matter annihilation or decay produces gamma rays. There are a variety of instruments observing the gamma-ray sky from tens of MeV to hundreds of TeV. Some make deep, focused observations of small regions, while others provide coverage of the entire sky. Each experiment offers complementary sensitivity to dark matter searches in a variety of target sizes, locations, and dark matter mass scales. This book provides a concise review of recent experiments.