Years and years ago I read every Hercule Poirot novel Agatha Christie wrote... and a few Jane Marples - Agatha again. Love them.
Got into Dick Francis for a while... but never liked him nearly as much as Agatha.
Read Sherlock, whom I liked... but didn't really love. Bit too 'fantastical'. Then began searching and reading various other Murder Mystery authors but never found any I liked as much as Agatha... and eventually.. gave up trying.
Trying to get back into it because... well, nothing like a good Whodunit. I had never read Nero Wolfe, fictional detective...author is Rex Stout. Quite famous. I'm half way thru my first Nero Wolfe novel and I like it, I will be reading another... BUT... he's not Agatha, or at least he isn't to me in the ONE novel..not sure how many he write but I think several.
So, your mission should you choose to accept it.... who in YOUR opinion is a great Whodunit author... writing novels with 'believable clues', (even if amazing), and the entire purpose is to 'guess' "whodunit" - JamesJM
