Along the way, though, I had come to avoid most of what he wrote as an older man. Some of his later books seem a bit bitter. So, I'm pleased to note that the latest book of his to cross my path, Sheiks & Adders, c. 1982, a book written when he was quite old, isn't bitter at all, but comes across as written by an old man who has decided to be indulgent toward the younger generations. It harks back to his early days, brimming with highly unlikely circumstances and strange characters getting embroiled in ridiculous (but dangerous) situations. If you don't go into it expecting a great mystery novel (it is, in fact, very vague on the mystery side of things, the mystery apparently being an excuse to get our hero out of the house and amongst strange happenings and in contact with people who need a dose of his wisdom), but merely want a light diversion with a bit of social commentary, it'll do. The opening is worrisome in that it makes it appear the book will be thick with the finer points of the history of language, but I assure you that doesn't happen. And, a plus: the Boy Scouts are allowed to make a few appearances and are even allowed to help our hero Sir John Appleby.
The book is still in print.
Sheiks and Adders
In fact, now that I take a look, I see that many of his books (he was prolific, no question) are back in print, thanks to House of Stratus. If you aren't familiar with his work, may I suggest you start with one of his earliest books?
The Secret Vanguard
...Oh, sure. Just my luck. One of my favorites, Lament for a Maker, seems to be, at present, out of print again. (Or maybe it is just temporarily out of stock at Barnes & Noble?) I'm not the only one who likes this one. I've seen it held up as one of the best-written mystery novels of all time. I'm not sure I'd go that far, but if you only read one book by this author, this would likely be a good one to pick.
Lament for a Maker: A Sir John Appleby Mystery
P.S. J.I.M. Stewart wrote a memoir, Myself and Michael Innes, but I can't say I'd recommend it, if for no other reason than I liked the author less after I read it. He comes across better in his fiction, I'd say.