A master key to the hidden order of the insect world. Every family finds its place. Charles T. Brues's authoritative key, originally issued in the Museum of Comparative Zoology at Harvard College, functions as an entomology reference guide and an insect taxonomy handbook, laying out concise, comparative criteria that make insect family classification approachable for students and dependable for specialists. It reads as a clear zoological identification manual rather than indulgent scholarship: practical keys and precise family accounts turn complex variation into usable steps, making it equally valuable as a field biologist resource and a reference for institutional collections. Measured, lucid prose frames diagnostic characters so that the logic of classification is as instructive as the determinations themselves; the balance of precision and accessibility gives new readers a confident entry to systematic entomology while serving as a reliable aid during laboratory or field identification. Republished by Alpha Editions in a careful modern edition, this volume preserves the spirit of the original while making it effortless to enjoy today - a heritage title prepared for readers and collectors alike. More than a technical handbook, this museum scientific bulletin belongs to the comparative zoology series and bears witness to early 20th century science emerging from Harvard natural history. Its methodical treatment of terrestrial arthropod taxonomy secures a place in any academic research collection and in the wider story of Charles T. Brues's works; casual readers interested in natural history will find lucid, explanatory passages, while classic-literature collectors and institutional curators will recognise its value as a cultured, authoritative piece of scientific heritage. The book's careful organisation and concise diagnostics make it a practical classroom and field companion, offering readers historical perspective on the development of insect family classification and an unobtrusive, instructive view into the foundations of modern systematic entomology. It remains a lively reference for anyone drawn to the craft of classification and the quiet authority of museum scholarship.