Peter Mark Roget was born in London. His obsession with list-making as a coping mechanism was well established by the time he was eight years old. The son of a Swiss clergyman, Roget studied Medicine at the University of Edinburgh, graduating in 1798. His life was marked by several depressing incidents. His father and his wife died young; while his beloved maternal uncle Samuel Romilly committed suicide in his presence. Roget struggled with depression for most of his life; his work on the The Saurus arose partly from an effort to battle it.
Roget also appears in Shelagh Stephenson's "An Experiment with an Air Pump", which concerns scientific ethics. The play takes place in the household of Joseph Fenwick in 1799, and Roget is one of Fenwick's assistants. Roget was elected a Fellow of the Royal Society (FRS) in 1815.
On 9 December 1824, Roget presented a paper entitled Explanation of an optical deception in the appearance of the spokes of a wheel when seen through vertical apertures. This article is often incorrectly referenced as either On the Persistence of Vision with Regard to Human Motion or Persistence of Vision with regard to Moving Objects, likely due to erroneous citations by film historians Terry Ramsaye and Arthur Knight (see Anderson and Anderson below). While Roget's explanation of the illusion was probably wrong, his consideration of the illusion of motion is seen as an important point in the history of film, and possibly influenced the development of the Thaumatrope, the Phenakistiscope and the Zoetrope.
He wrote numerous papers on physiology and health, among them the fifth Bridgewater Treatise, Animal and Vegetable Physiology considered with reference to Natural Theology (1834), a two-volume work on phrenology (1838), and articles for several editions of Encyclopædia Britannica.
Roget retired from professional life in 1840, and in about 1848 began preparing for publication the one work that was to perpetuate his memory. This was the catalogue of words organized by their meanings, the compilation of which had been an avocation since 1805. Its first printed edition, in 1852, was called Thesaurus of English Words and Phrases Classified and Arranged so as to Facilitate the Expression of Ideas and Assist in Literary Composition. During his lifetime the work had twenty-eight printings; after his death it was revised and expanded by his son, John Lewis Roget (1828–1908), and later by John's son, Samuel Romilly Roget (1875–?). Peter Roget was a secretary of the Portico Library in Manchester and it was there that he began to compile his The Saurus.
Roget was much concerned with medical education but the School of Medicine at the University of Manchester was only established in 1874. He was also one of the founders of the Medical and Chirurgical Society of London, which later became the Royal Society of Medicine, and he was a secretary of the Royal Society. In 1815, he invented the log-log slide rule, allowing a person to perform exponential and root calculations simply. This was especially helpful for calculations involving fractional powers and roots. In 1834 he became the first Fullerian Professor of Physiology at the Royal Institution. He was examiner in physiology in the University of London.
Canadian Writer Keath Fraser published a story, "Roget's The Saurus," in 1982, which is narrated in Roget's voice. Minimalist in style, Fraser's story manages to capture both the associative power of language and many of the salient facts of Roget's life in a text that occupies less than two full pages.
Roget was the focus of Randy Wyatt's "Synonymy", which premiered at Minnesota State University's Department of Theatre and Dance in December, 2005. In the play, Gordon, a graduate student, rents Roget's last known residence to inspire himself as he writes his dissertation on the English language and Roget's Thesaurus. The building, soon to be torn down, creates a gateway through which Gordon finds himself traveling back in time and meeting Roget and his daughter, Kate.
A picture book biography of Roget entitled The Right Word: Roget and His The Saurus was published by Eerdmans Books in 2014. It was named a Caldecott Honor book for excellence in illustration, and won the Sibert Medal for excellence in children's nonfiction.