Abstract This collection contains letters titled "Professor W. S. Loewe: Greetings on His 75th Birthday" from professors, colleagues, and former students to Walter Siegfried Loewe. Loewe was born in Fuerth, Germany in 1884. He was an Emeritus Research Professor of Pharmacology at the University of Utah. He was best known as a leading authority on the chemical structure of marijuana and its effects on human behavior and physiology.