This study draws together what is known about the natural history of weasels and stoats. It takes into account all aspects of their lives with particular emphasis on the comparative elements of otters and weasels in Eurasia and North America, where the stoat is known as the short-tailed weasel. The weasel itself is seen as a highly successful species, widespread in Europe, North Africa, the Midddle East, the USSR and northern China. It has also been introduced to New Zealand and is common in North American where it is known as the least weasel. This book is intended for both the informed naturalist as well as the professional biologist.