[1] With Clinton Davisson, he proved the wave-particle duality of matter in the Davisson–Germer experiment, which was important to the development of the electron microscope.

A former fighter pilot in World War I, Germer subsequently worked at Bell Labs in New Jersey.

He climbed widely around the Northeast United States, and especially at New York's Shawangunk Ridge.

Although the Appalachian Mountain Club was dominant in the area at the time, and strictly regulated rock climbing, Lester was never associated with the club, and found himself in conflict with the leading climber in the area, Hans Kraus, who was head of the AMC's Safety Committee.

Until that moment, Lester had a 26-year perfect safety record in rock climbing; he had never even taken a leader fall.