I like to read books that offer me some sort of challenge, but in between I like to slip in fun books like those written by P.G. Wodehouse, John D. MacDonald and Robert Parker (although I've cooled to him, as his books became so formulaic in the last 10 or 20 years). My mom consumed more mystery novels than anyone I know, and although I've found I don't like Agatha Christie much, I do occasionally like to read a book by P.D. James or Ngaio Marsh. Marsh, who was a New Zealander, has one of the greatest names ever and I find myself regretting my wife and I didn't name one of our daughters Ngaio. She's also a confident and accomplished writer, presenting the cases her protaganist, Chief Inspector Roderick Alleyn, solves with flair and precision. I read "Hand in Glove," one of 32 Alleyn mysteries published from 1934 to 1982, which was the year Marsh died.
"Hand in Glove" was published in 1962, but its class tensions and romantic sub-plot could have been set at just about any point in 20th century England. Marsh's expert plotting moves the story along, and since the book is short to begin with, it's done before you know it -- a zesty snack between meals.