This book discusses the taxonomy, distribution, and nesting biology of each species and subspecies of yellowjacket worldwide. Keys to the subgenera and all species worldwide are also provided. These wasps are distributed widely throughout the the Holarctic, extending into the Malayan Pennisula in the east and Guatemala and Honduras in the west. Adults are generally of a small size varying in length from 1.5-2.0 cm and are usually colored yellow and black, but they may also be black and white, and may have brown, red or orange markings. Traditionally yellowjackets are divided into two genera Dolichovespula and Vespula, but in this book 10 subgenera, 60 species, and 30 subspecies are recognized. These are as follows: Pseudovespula with 3 species, and 6 subspecies. Dolichovespula with 4 species, and 1 subspecies. Boreovespula with 12 species, and 4 subspecies. Metavespula with 2 species, and 1 subspecies. Vespula with 2 species, and 3 subspecies. Allovespula with 9 species, and 5 subspecies. Lineovespula with 2 species, and 1 subspecies. Griseovespula with 2 species. Paravespula with 9 species, and 7 subspecies, and Rugovespula with 3 species, and 3 subspecies.