I just finished reading Ed McBain's "The Frumious Bandersnatch", and I'm a little sad. It's not a bad book, still better than a lot of what's out there, but it's nowhere near the quality of the old 87th Precinct books. There's only one crime, rather than the two interleaving and reflecting ones that he used to have, and, worse, I 'got it' about halfway through. He's been writing these books since the fifties, and it's starting to look like time to go. (Nice to see Ollie Weeks maybe falling in love, though).
Another one that was REALLY sad, was the last Dick Francis book. It read like someone had taken a Dick Francis plot outline, and just slapped together a book out of it (I understand that this is pretty well what happened, his wife mostly wrote the book). All of the life and sparkle, the 'Francis-ish-ness' was gone.
What do you think? Should authors let go and stop writing when they are starting to lose it? CAN they, when this is what they've been doing for the last sixty years?