Sexton Blake is a fictional British detective, who appeared in stories published over eight decades from 1893 to 1978. Blake featured in more than 4,000 stories by approximately 200 different authors, making him one of the most prolifically chronicled characters in English literature. The detective's adventures spanned multiple formats including comic strips, novels, radio serials, silent films, and a 1960s ITV television series, reaching audiences across Britain and internationally in various languages.

Initially conceived as a Victorian gentleman detective, Blake evolved significantly over time, acquiring now-iconic elements like his Baker Street residence, his young assistant Tinker, his bloodhound Pedro, and his housekeeper Mrs. Bardell. While often compared to Sherlock Holmes, Blake's adventures typically featured more action-oriented plots and colourful adversaries, including memorable villains like Zenith the Albino, George Marsden Plummer, Dr. Huxton Rymer, Leon Kestrel, Waldo the Wonderman and the Criminals' Confederation. The character reached his peak popularity during the 1920s and early 1930s, particularly through publications like The Union Jack and The Sexton Blake Library, which at its height published five times monthly.

The first Sexton Blake story was "The Missing Millionaire". Written by Harry Blyth (using the pseudonym Hal Meredeth), it was published in The Halfpenny Marvel number 6, on 20 December 1893, a story paper owned by the Amalgamated Press. Blyth wrote six more Sexton Blake tales, three for the Marvel and three for The Union Jack a story paper launched in April 1894.

The Amalgamated Press purchased the copyright to Blake along with the first story Blyth had submitted and from 1895 onwards several authors began to pen Blake tales. From August 1905 Blake became the resident character in Union Jack, appearing in every issue until its transformation into the Detective Weekly in 1933. Blake continued as the main feature until Detective Weekly ended in 1940.

Blake's popularity began to grow during the Edwardian era, and he appeared in a number of different story papers. These appearances included serials in the tabloid sized Boys' Friend (1905), complete tales in the pocket-sized Penny Pictorial (from 1907 to 1913 (when that magazine ended), and short stories in Answers, (1908–1911) one of the Amalgamated Press' most popular papers. Writers from this era include: William Murray Graydon, Maxwell Scott, Norman Goddard, Cecil Hayter, D. H. Parry, E. W. Alais, W. J Lomax, and Michael Storm.

In the second decade of the 20th century, new writers joined the ranks and created the formidable master criminals that matched wits with Blake. These include Andrew Murray, Anthony Skene, Robert Murray Graydon, Edwy Searles Brooks and George Hamilton Teed.

Longer tales of 60,000 words or so appeared in The Boys' Friend Library and the success of these led to the creation of The Sexton Blake Library in 1915. This digest-sized publication specialized in longer tales, and at the height of its popularity was published 5 times a month. It ran for just under 50 years.

The majority of Sexton Blake Library covers (prior to editor William Howard Baker's 1956 revamp of the character) were painted by master Sexton Blake illustrator Eric Parker