The 16 contributors who produced the 15 chapters in Robert Usinger's Aquatic Insects of California (AIC), published by the University of California Press in 1956, included accomplished taxonomists experienced with aquatic insects, others who specialized in nonaquatic insect groups, and still others who were self-trained or worked in nonacademic positions. Richly illustrated, AIC provided species-level keys to adults of most insect groups, a feature not seen in subsequent identification guides to North American aquatic insects. This change might reflect the recent trend of reliance on identifications to higher taxonomic levels in benthic studies, particularly in biomonitoring, and less emphasis on association of adult and immature stages of aquatic insects. Ecological information presented in AIC emphasized mosquito control and anxieties about potential malarial outbreaks and the importance of aquatic insects in sewage treatment. Detailed sampling methods for streams reflected those being developed in California because few descriptions of stream sampling methods were then available. The role of the taxonomist who was self-trained, nontraditionally employed, or had broad-based interests might have parallels today. Identification advances in benthic biology are now being done more often by biomonitoring researchers in government laboratories and consulting firms than in university research programs.