It occurs to me - somewhat belatedly, I admit - that there can be no more appropriate day than Halloween to enjoy a good seasonal mystery. That being the case, I have a few treats up my sleeve - and the authors, of course, may be relied upon for the tricks. So here's some murder and mayhem that may appeal to you today.
I think one of the best is Agatha Christie's "Hallowe'en Party," a Hercule Poirot novel in which a child is murdered at a Halloween party after announcing that she had once witnessed a murder. As usual with Christie, it is well-plotted, and it's one of her later books, having been published in 1969.
Or, if you're a fan of Albert Campion, there is Margery Allingham's "Death of a Ghost." It's not a Halloween mystery as such, but surely the titular ghost would feel at home at a seasonal celebration. It's a cross between a puzzle mystery and a fine thriller - we have identified the killer well before the end, and the problem becomes one of proof, not to mention the safety of Mr. Campion and others.
Along the same lines, Carter Dickson's The Skeleton in the Clock is not tied to this holiday, but surely the perambulating skeleton in this book would be right at home at a Halloween party. Add that to the rather nightmarish events in the book, and you have a fine impossible murder, with Dickson's sleuth, Sir Henry Merrivale, roaring around the countryside trying to prevent another murder. This one is long out of print, but Amazon's second hand dealers appear to have a lot of different editions, most inexpensive.
I'll make a note to myself to review these next year ahead of Halloween - but why wait? Your favorite mystery bookstore can find these for you - or, if you prefer Amazon and use my links above, I will get a few cents on your purchases, for which I thank you.