The wisent, the largest and heaviest land mammal in Europe, narrowly escaped extinction in the 20th century, sharing a fate similar to that of the aurochs. The last free-ranging lowland wisent was shot in Poland in 1919, and the Caucasian or mountain wisent became extinct in 1927. With the few remaining animals in human care, European zoos began a breeding program that, despite numerous setbacks, proved to be successful. Today, wisent populations once again exist in the wild in five European countries, with the largest population currently exceeding 400 animals in the Bialowieza Forest in Poland. The author couple, who have been engaged in wisent research in Bialowieza for decades, paints a vivid picture of this fascinating and impressive wild cattle species in the present monograph. A significant portion is dedicated to documenting the painstaking reintroduction efforts.