The article discusses two classic books on diving, "Shallow Water Diving for Pleasure and Profit" (1950) and "Shallow Water Diving and Spearfishing" (1954), written by Hilbert Schenck and Henry Kendall. These books document the transformation of diving from a professional activity to a sport. The authors, Schenck and Kendall, had backgrounds in diving technology and presented the material in a methodical and interesting manner. The books cover various diving technologies, including helmets, wet/dry suits, and spearguns, and provide tips on how to go about diving. The authors' lives and accomplishments are also briefly discussed. [Extracted from the article]