Here are a few books and detectives that were made into films. Phillip Marlowe (Raymond Chandler’s detective) and Sam Spade (Dashiell Hammett’s character) were so defined by Humphrey Bogart – even though both were also portrayed by other actors – that it doesn’t matter whether or not they were true to the book character.
Agatha Christie – Miss Marple has been portrayed by three different actresses in 12 films. The portrayal closest to the book character, according to Dame Christie herself, is by Joan Hickson in the BBC movies. – Hercule Poirot was probably played best in films by Albert Finney (check out Murder on the Orient Express, 1974), but thanks to TV Poirot became best known by the David Suchet portrayal.
The Big Clock – by Kenneth Fearing was made into film twice; first as The Big Clock starring Ray Milland & Charles Laughton and then as No Way Out starring Kevin Costner & Gene Hackman. No Way Out, while enjoyable, is so loosely based on the book I would recommend trying to find the original, black & white, 1948 version.
Darker Than Amber – by John D. MacDonald. To my knowledge it isn’t out on VHS or DVD, but if you get a chance to see it on late-night TV don’t miss it. Starring Rod Taylor and Jane Russell, it is possibly the best of the Travis McGee movies.
Devil In A Blue Dress – by Walter Mosely. The ending is different than in the book, but the film is excellent. Denzel Washington is Easy Rawlings, but the star of the film is Don Cheadle as Easy’s friend “Mouse”, a role that won him a Best Supporting Actor Oscar.
The Jessie Stone series – by Robert B. Parker. These films were made-for-TV and star Tom Selleck. Tom Selleck IS Jesse Stone. (Even Parker thinks so.)
Kiss Me Deadly – by Mickey Spillane. Several actors have played Mike Hammer, both in film and on TV but this is the one to watch. Starring Ralph Meeker, it doesn’t follow the book completely but the portrayal of Hammer is the best.
Mute Witness – by Robert L. Fish. The movie is Bullitt with Steve McQueen. The story has moved from NYC to San Francisco and there are some other minor changes, but the movie contains one of the most famous car-chase scenes in film.
The Saint series – by Leslie Charteris. The 15th book in the series, The Saint in New York, with Louis Hayward, was the first to become a film. However, George Sanders, who played in later Saint films, is considered to be the best. Look for The Saint in London (1939).
Sherlock Holmes series – If you want to compare Holmes portrayals watch The Hound of the Baskervilles. The 1939 film stars Basil Rathbone, the 1959 flick has Peter Cushing, the 1983 version features Ian Richardson and the made-for-TV movie (1988) is with Jeremy Brett. You decide who makes the best Holmes!