His research focussed on the stereochemistry and conformational analysis of flexible organic molecules, including derivatives of cyclohexane and saturated heterocyclic rings, using nuclear magnetic resonance spectroscopy (NMR) extensively. His 1962 textbook Stereochemistry of Carbon Compounds influenced generations of organic chemists.[1] The most recent edition is Stereochemistry of Organic Compounds, co-authored in 1994 with Samuel H. Wilen.[1][5]