The breeding of Mules and Hybrids has a remarkable hold on a very large number of people. Why this should be is difficult to explain. A perfect example of a rare cross seems to stimulate those who have not been able to produce such a thing, and they are determined to "have a go," while those who have been successful once, twice or even three times like to go on and on. This early work on birds is both expensive and hard to find in its first edition. It contains details on the characteristics of hybrid bird species such as the bullfinch, chaffinch, redpoll and many more. This is a fascinating work and thoroughly recommended for anyone interested in ornithology.