Paul Emil Flechsig (29 June 1847, Zwickau, Kingdom of Saxony – 22 July 1929, Leipzig) was a German neuroanatomist, psychiatrist and neuropathologist.

Flechsig was the treating psychiatrist for Daniel Paul Schreber, whose memoir inspired Sigmund Freud to publish a detailed analysis of the case in 1911.

He is the chief exponent of that phase of neuro-anatomy which deals mainly with distribution and the course of nerve fibers, their formation into systems, and their mutual relationship.

Flechsig was so enthusiastic about his method that he utilized it with some success in establishing what he called association centers which he believed are the seats of psychic activity.

Because of Flechsig's high position in science, his clinic and laboratory were visited by many famous scientists, of whom he briefly speaks in the first part of the booklet where he gives a brief sketch of his life.

Generally this little book is a brief summary of the advances made by Flechsig and his school in the field of brain anatomy during an unusually fruitful period of activity covering fifty- five years.