Guess The Genre #1934 (Gathered by Ken Anderson)

BasilRathboneSherlockHolmes SidneyGreenstreetNeroWolfe
StanPurdyMikeHammer LonClarkNickCarter
HowardDuffSamSpade DickPowellPhilipMarlowe
ShellyMannPeterGunn EdwinAstleySimonTemplar
MikePostJimRockford RichardRoundtreeJohnShaft

Answer: Private Investigators - Next is Guess the Genre #1935

Or, I don't want to guess - Show Me A List