This book was originally published in 1870. At the time, George Mackenzie Bacon was a medical superintendent at Cambridgeshire County Asylum (now Fulbourn Hospital) near Cambridge, England. The slim volume offers Bacon's observations on the idiosyncrasies of his patients' handwriting.

Following On the Writing of the Insane is Bacon's annual Report of the Medical Supervisor from 1880, featuring tales of trepanation, hydrocephaly, and more.