Recently I read two mysteries with a revive-somebody-old theme. One of them was a recent Sherlock Holmes novel (Grandpa Squirrel lent it to us), not bad reading but with really a nasty crime at the bottom of it. The other was a novel set in 1934 and starring the real-life mystery writer Josephine Tey as one of the main characters. I finished it dutifully, but I really disliked it, for several reasons. I never did figure out that blackmail subplot. And Josephine Tey didn't even get all that much to do in solving the mystery. Besides, as someone else pointed out, Josephine Tey was just one of her pen names anyway, so it's not very believable that her closest friends would have called her that.
It wasn't until I got partway through Rumpole and the Golden Thread this week that I realized what was missing in those other books. Humour.
And besides the frequent quotes and misquotes from The Oxford Book of English Verse, they enrich my vocabulary immensely with words like plonk.
P.S. Grandpa Squirrel says he likes them just for the cover art.