Howard Evans was a brilliant ethologist and systematist, describing over 900 species in over a dozen entomology and natural history books. Upon his death in 2002, he left behind an unfinished manuscript, intended as an update of his classic 1966 work, The Comparative Ethology and Evolution of the Sand Wasps. O'Neill, Evans's former student and coauthor, has completed and enlarged this work into a tribe-by-tribe, species-by-species review of Bembicinae studies from the last four decades.