Why did Mr Z call a fork a thermometer when he was perfectly capable of using it to eat with?

Why did Mr S exclaim in grammatical gibberish whenever he heard the word “thermometer”?

Why did Mr L always reply with gestures while calling out “tan, tan”?

Why did Mr D transform the words he heard so that “tortue” (turtle) became the meaningless “torpee”, “araignée (spider) became “alougrée” and “revolver” “reveltil”.

These men were not Surrealist poets but victims of brain damage. The study of their pathologies offers a fascinating insight into the workings of the brain.

Written in the form of a detective novel, this major work of neuropsychology approaches the subject without dogmatism and actively enrols the reader in seeking and developing a diagnosis.

L'Homme Thermomètre is in much the same vein as Oliver Sacks' immensely successful The Man Who Mistook His Wife for a Hat. It describes a number of fascinating and moving cases.

Laurent Cohen is a professor of neurology at the teaching hospital La Pitié-Salpêtrière-University of Paris-VI.