Here, as discussed in the bonus episode, are the covers of the editions of Killer's Wedge that we have. Left to Right, Paul's copy is the 1978 Penguin Edition, Stevo's is the 1979 Penguin and Morgan's is the 2007 Allison and Busby edition (featuring shattered glass, which in no way relates to the story).
Earlier editions focused, quite reasonably, on the most important non-cop character, Virginia Dodge, although the difference between her portrayal on the original hardback (L) and the paperback (R) perhaps tells you something about the different approaches/markets the editions were aimed at!
And at least one edition (Signet) doesn't bother to play with the main-plot at all, but goes straight in for a spoiler about Carella's discovery/showdown/fistfight from his B-Plot "Locked Room" mystery:
Still, they're all better than the currently available Thomas and Mercer edition (Amazon), to the extent I'm not even going to link to the image. Remember - buy second-hand! Support independent booksellers! Enjoy the thrill of the book hunt!