Very mixed bag today, I thought. Some very neat, simple clues that still have a satisfying PDM (9A, 23A), but others should never have made it past the editor. As far as I can make out, 4D includes a one-letter abbreviation for money that I doubt anyone has ever used. As for 13D -- okay, it's a practice that aficionados may know, but the rest of us are forced to scour Google, especially as the clue is ludicrously convoluted (half of one word, another word, the final letters of two more words with scarcely an indication of what you're meant to do with them ... unless part 2 of the clue is 21A)?! All very clever, what with the &Lit aspect and all, but not what I'd call fair.