Speaking of concise but elegant works on interesting subjects. The Penguin Lives Series is another good example. I have mentioned this series before (here is my review of Paul Johnson’s volume on Napoleon).
Recently I picked up new volumes on Winston Churchill (by John Keegan); Mao Zedong (by Jonathan D. Spence); and Pope John XXII (by Thomas Cahill). What a great way to learn about some crucial figures in history without having to read a thousand pages in a multi-volume biography. The subjects range from Dante and Budha to Marcel Proust and Rosa Parks. As they say on TV, they make great gifts too!