Europe: eastward to include Finland, Poland, Romania and the Balkan Peninsula (but not the Ukraine); southward to include the principal Mediterranean islands (not those close to Turkey); westward to the Atlantic coast; and northward to include the Arctic region.
All species, and their principal subspecies, forms and variations.
Comparisons between similar-looking species.
A consistent and fundamental method of analysis of butterfly wing-patterns is presented and used to describe in detail variations within the same species and between related species. In a number of cases new identification characters are identified and some widely accepted ones qualified.
Every species is illustrated by numerous pictures published at the same scale, each accompanied by pertinent text. Usually they are organised geographically, so that altogether they build to a portrait of the species as a whole.
Sample downloads illustrate the foregoing comments.