The strikeout is one of the most exciting plays in baseball, and these 50 pitchers are better at it than anybody in the history of the game.
However, piling up K's isn't just about throwing hard (although the ability to hit triple digits on the radar gun certainly helps); it's about attacking hitters with your best stuff and challenging them to hit it. It's about being a fearless competitor on the mound and not being afraid to ruffle some feathers when the time calls for it.
Pitchers seem to be getting increasingly good at this too, as evidenced by the amount of active players you'll find on this list. But heat is still heat regardless of the era, so there'll be lots of names you've probably heard of and a few names you haven't.
Note: No attempt was made to rank these pitchers because it's impossible to compare them across different eras. They are instead sorted alphabetically.