Brucellosis, a bacterial disease, was first noted in the Greater Yellowstone Area in 1917 and has been a chronic presence there since then. This book reviews existing scientific knowledge regarding brucellosis transmission among wildlife, particularly bison, elk, and cattle, in the Greater Yellowstone Area. It examines the mechanisms of transmission, risk of infection, and vaccination strategies. The book also assesses the actual infection rate among bison and elk and describes what is known about the prevalence of Brucella abortus among other wildlife.