Note: Generally known as Basil of Baker Street (eg, Wikipedia).
Some library records report "A Basil of Baker Street Mystery" as series title or book subtitle.
Basil the detective and Dr. Dawson, his companion and biographer, live in Holmestead, a mouse village in a Baker Street basement. Sherlock Holmes and Dr. Watson live upstairs in 221B, where Basil learned scientific detection by eavesdropping Holmes.
Disney approved the Basil of Baker Street series for loose adaptation as an animated feature film in 1982. New management in 1985 renamed it The Great Mouse Detective and so it was released in 1986. In 1992 it was re-released as The Adventures of the Great Mouse Detective. The adaptation remains in London, as Doyle's Holmes often does, and Titus's Basil never does. "Basil, the Great Mouse Detective" (1987) is the film story.