The need for a new monographic treatment of the genus Lesquerella (mustard family) has been evident for many years. Authors Reed Rollins and Elizabeth Shaw summarize three decades of field, greenhouse, and herbarium research in this detailed study of the North American species of the genus, including L. arctica. They cover sixty-nine species and twenty-nine infraspecific taxa that range in occurrence from the arctic to southern Mexico. Nearly sixty photographs and maps document their text.