This book provides essential information on 12 cockroach assemblages with more than a thousand specimens analyzed and investigates the Jurassic site in Bakhar, Mongolia, as one of the most diverse fossil insect sites worldwide. The findings presented here include 32 new cockroach species (of a total of 300 Jurassic species described worldwide). Since several individuals of each species are investigated, the book is the first that contains information on the variability of an Upper Jurassic organism. The wings of the cockroach specimen only rarely show wing deformations, suggesting that the ecological conditions at Bakhar were optimal during that time. The book’s content is clearly structured, moving from collection methods, to phylogenetic analyses, to a comparison of global fossil sites. Given its scope, the book appeals to all (Jurassic) paleontologists, botanists and paleoentomologists, as it offers an unbiased counterpart to the extensively studied Daohugou site in China. It is also useful in the mining industry, as the strata contain strategic coal (and other materials).