Two John Perrys, different initials

One letter, especially if it’s a middle initial of a person’s name, can make a difference. Consider the case of two John Perrys.

John R. Perry is a professor of philosophy, who among many other things devised the Theory of Structured Procrastination, for which he was awarded the 2011 Ig Nobel Prize in literature.

John D. Perry is an inventor, who wrote “A Pictorial History of Insertable EMG Sensors“,which is all about vaginal sensors (electromechanical sensors inserted into vaginas for monitoring, assessment, or other purposes), one of which is pictured here.