Field guide

A field guide is a book designed to help the reader identify wildlife (flora or fauna or funga) or other objects of natural occurrence (e.g. rocks and minerals).

[1] Field guides are often designed to help users distinguish animals and plants that may be similar in appearance but are not necessarily closely related.

Perhaps the first popular field guide to plants in the United States was the 1893 How to Know the Wildflowers by "Mrs. William Starr Dana" (Frances Theodora Parsons).

[4] In 1934, Roger Tory Peterson, using his fine skill as an artist, changed the way modern field guides approached identification.

For general public use, the main function of a field guide is to help the reader identify a bird, plant, rock, butterfly or other natural object down to at least the popular naming level.

To this end some field guides employ simple keys and other techniques: the reader is usually encouraged to scan illustrations looking for a match, and to compare similar-looking choices using information on their differences.

[5] Insect guides tend to limit identification to Order or Family levels rather than individual species, due to their diversity.