Peter Mark Roget was a British physician, natural theologian, lexicographer, and founding secretary of The Portico Library. He is best known for publishing, in 1852, the Thesaurus of English Words and Phrases, a classified collection of related words (thesaurus). He also read a paper to the Royal Society about a peculiar optical illusion in 1824, which is often regarded as the origin of the persistence of vision theory that was later commonly used to explain apparent motion in film and animation.

The Portico Library, The Portico or Portico Library and Gallery on Mosley Street in Manchester, England, is an independent subscription library designed in the Greek Revival style by Thomas Harrison of Chester and built between 1802 and 1806. It is recorded in the National Heritage List for England as a Grade II* listed building, having been designated on 25 February 1952, and has been described as "the most refined little building in Manchester".