The Scientist interviews other sleep medicine professionals for their remembrances of Christian Guilleminault.

In an email to The Scientist, Emmanuel During, a sleep specialist at the Stanford Sleep Medicine Center who trained under Guilleminault, says, “CG always emphasized that sleep was a brain phenomenon, i.e. produced by the brain and benefiting the brain.” This led him to focus on the brain in his investigations of sleep-related breathing disorders, while most researchers who studied these conditions were trained in pulmonary medicine. For instance, as During points out, “CG never reduced obstructive sleep apnea to a mere obstructive phenomenon, but looked at what our brains would tell us about our sleep.”