author
A 19th-century physician and asylum proprietor, he wrote about mental illness at a time when psychiatry was still taking shape. His work is tied to the reform-minded world of High Beach asylum in Epping Forest, later remembered in accounts of poet John Clare and in historical fiction.

by M. (Physician) Allen
Matthew Allen was a British physician best known for Essay on the Classification of the Insane (1837), a medical work on mental illness published under the name M. Allen, M.D. Surviving records of the book and later references to Allen connect him with the treatment and classification of insanity during the early Victorian period.
He is also remembered as the doctor who ran the private asylum at High Beach in Epping Forest. Later sources describing John Clare's stay there portray Allen as part of a more reforming approach to asylum care, one that aimed to avoid harsh restraint and offered patients greater freedom than many institutions of the time.
Some modern readers may know him through the historical afterlife of High Beach: Allen appears as a real-life figure behind books and articles about John Clare, Alfred Tennyson, and the unusual literary circle that gathered around the asylum. I wasn't able to confirm a reliable portrait image from the sources I found, so none is included here.