The fourth volume of the Guide to the Butterflies of the Palearctic Region covers an additional 56 species of Satyrinae belonging to the Subtribes Melanargiina and Coenonymphina.
Highly valuable sources of information for the preparation of this book have been the works on Melanargia by S. Wagener and the Coenonympha revision by D. Davenport.
Nevertheless, the availability of new material from previously little known areas, together with taxonomists' current view that restricts the subspecific rank to taxa with well-defined and constant diagnostic morphological features, have led to a number of changes in previous taxonomic arrangements, including reducing into synonymy some old taxa.
Although one of the main purposes of this book is to clarify and simplify previous taxonomic arrangements, made heavy by too many confusing taxa, the introduction of a new subspecies of Melanargia asiatica has become necessary in order to identify a population showing clear and constant peculiar morphological features.