Read the books. Watch the movies. Check out these great book/movie combos.
Amateur Detectives:
Albert Campion created by Margery Allingham [1]
Nick Charles and Sam Spade created by Dashiell Hammett [2]
Miss Marple created by Agatha Christie [3]
Ellery Queen created by Ellery Queen [4]( Frederick Dannay & Manfred Lee)
Lord Peter Wimsey created by Dorothy Leigh Sayers [5]
Historical Mysteries
Brother Cadfael [6]created by Ellis Peters
Wilkie Collins [7]the first modern mystery writer
Police Detectives
Adam Dalgliesh [8]created by P. D. James
Inspector Alleyn [9]created by Naigo Marsh
Inspector Lynley [10]created by Elizabeth George
Inspector Morse [11]and Inspector Lewis created by Colin Dexter [12]
Private Detectives
Sherlock Holmes [13]created by Arthur Conan Doyle
Phillip Marlowe [14]created by Raymond Chandler
Hercule Poirot [15]created by Agatha Christie
Spenser created by Robert B. Parker [16]
Nero Wolfe [17] created by Rex Stout
Links:
[1] http://catalog.btpl.org/search~S5?/aAllingham+Margery/aallingham+margery/1%2C2%2C26%2CE/2exact&FF=aallingham+margery+1904+1966&1%2C25%2C
[2] http://catalog.btpl.org/search~S5?/aHammett%2C+Dashiell%2C+1894-1961./ahammett+dashiell+1894+1961/-3%2C-1%2C0%2CE/2exact&FF=ahammett+dashiell+1894+1961&1%2C29%2C
[3] http://catalog.btpl.org/search~S5?/aChristie+Agatha/achristie+agatha/1%2C3%2C265%2CE/2exact&FF=achristie+agatha+1890+1976&1%2C263%2C/indexsort=-
[4] http://catalog.btpl.org/search/X?SEARCH=ellery+queen&searchscope=5
[5] http://catalog.btpl.org/search~S5?/aSayers+Dorothy+/asayers+dorothy/1%2C2%2C38%2CE/2exact&FF=asayers+dorothy+l+dorothy+leigh+1893+1957&1%2C37%2C
[6] http://catalog.btpl.org/search~S5?/apeters+ellis/apeters+ellis/1%2C2%2C43%2CE/exact&FF=apeters+ellis+1913+1995&1%2C42
[7] http://catalog.btpl.org/search~S5?/aCollins%2C+Wilkie%2C+1824-1889./acollins+wilkie+1824+1889/-3%2C-1%2C0%2CE/2exact&FF=acollins+wilkie+1824+1889&1%2C34%2C
[8] http://catalog.btpl.org/search~S5?/ajames+p+d/ajames+p+d/1%2C1%2C52%2CE/frameset&FF=ajames+p+d&9%2C%2C52/indexsort=-#
[9] http://catalog.btpl.org/search~S3?/aMarsh%2C+Ngaio%2C+1895-1982./amarsh+ngaio+1895+1982/-3%2C-1%2C0%2CE/2exact&FF=amarsh+ngaio+1895+1982&1%2C17%2C#anchor_13
[10] http://catalog.btpl.org/search~S5?/tInspector+Lynley/tinspector+lynley/1%2C28%2C53%2CE/2exact&FF=tinspector+lynley+mysteries&1%2C6%2C/indexsort=-
[11] http://catalog.btpl.org/search~S5?/tInspector+Morse/tinspector+morse/1%2C3%2C6%2CE/2exact&FF=tinspector+morse&1%2C4%2C/indexsort=-
[12] http://catalog.btpl.org/search~S3?/dMorse%2C+Inspector+%28Fictitious+character%29+--+Fictio/dmorse+inspector+fictitious+character+fiction/-3%2C1%2C0%2CE/2exact&FF=dmorse+inspector+fictitious+character+fiction&1%2C8%2C/limit?
[13] http://catalog.btpl.org/search~S3?/aDoyle+Arthur/adoyle+arthur/1%2C1%2C66%2CE/frameset&FF=adoyle+arthur+conan+sir+1859+1930&5%2C%2C66/indexsort=-
[14] http://catalog.btpl.org/search~S3?/aChandler%2C+Raymond%2C+1888-1959./achandler+raymond+1888+1959/-3%2C-1%2C0%2CE/frameset&FF=achandler+raymond+1888+1959&22%2C%2C25
[15] http://catalog.btpl.org/search~S3?/tHercule+Poirot++/thercule+poirot/1%2C8%2C59%2CE/frameset&FF=thercule+poirot+and+miss+marple+mystery&1%2C1%2C
[16] http://catalog.btpl.org/search~S5?/aParker%2C+Robert+B.%2C+1932-2010./aparker+robert+b+1932+2010/-3%2C-1%2C0%2CE/2exact&FF=aparker+robert+b+1932+2010&1%2C150%2C
[17] http://catalog.btpl.org/search~S3/