I've been reading the novels of Dorothy Sayers for the third time the last week. If you enjoy mystery novels at all, and don't know Sayers, you must check her out. Not only could she write mysteries, she was a brilliant thinker -- one of the first women to earn a degree from Oxford University, the originator of the Guinness ad campaign with the toucan, conversant in the latest intellectual advances, and a renowned translator of Dante -- and this powerful intellect is apparent in her works.
Part of the fascination of her work is the way in which she captures England on the cusp -- the pre-war England of Victoria was fading away, and the new England rising, but, in the 20s, both were visible, and Sayers brilliantly plays on the tension between the two. In ways, the 1920s were like a dress rehearsal for the 1960s, and Sayers also captures this spirit of social novelty: giant cocaine parties, unmarried couples living together, political radicalism, and so on.
Pick up a Sayers novel today! (Busman's Honeymoon may be one of the best.)
UPDATE: Here's Sayers on "The Lost Tools of Learning".