Studies in the Genus Cortinarius I by Alexander H. Smith is a comprehensive examination of the genus Cortinarius, particularly focusing on species found in Washington, Oregon, and northern California. Supported by grants from the Horace H. Rackham School of Graduate Studies at the University of Michigan, Smith conducted detailed field studies and collection efforts during 1935 and 1937. The work builds on the foundational contributions of C. H. Peck and C. H. Kauffman, extending their research to less explored regions such as southern Oregon and northern California. The book presents new species and varieties, critically identifies species not previously reported in North America, and provides extensive range extension notes. Smith underscores the challenges posed by the seasonal and sporadic appearance of agarics, which influenced the scope and results of past and current studies. The collections, deposited in the University of Michigan's Herbarium, also offer insights into habitat adaptability and species diversity within the genus. This scholarly work includes descriptions of various subgenera, detailed notes on morphology, and plates for visual reference, making it an essential resource for mycologists and enthusiasts interested in the genus Cortinarius.