Helm Identification Guides

The Helm Identification Guides are a series of books that identify groups of birds. The series include two types of guides, those that are:

Early volumes were sometimes published under the Croom Helm or Christopher Helm imprints. In addition, a parallel set of guides, very similar in design, was published by Pica Press in the 1990s (marked Pica in the list below); Pica was later absorbed into A & C Black (now part of Bloomsbury Publishing Plc), and all guides are now marketed as a single series.

Several of the books have won the British Birds Bird Book of the Year award. A list of titles in the series, in chronological order of publication, is as follows:

Note: 'nW' indicates those that do not have worldwide coverage.

...
Wikipedia