"The Secret Life of Words: How English Became English," by Henry Hitchings, will appeal not only  to crossword-puzzle freaks, lexicographers, linguists, historians, and English teachers but to anyone who is the least bit interested in how this mighty, worldwide language got so mighty and worldwide. 

Hitchings, author of "Defining the World: The Extraordinary Story of Dr. Johnson's Dictionary," traces the origins of hundreds of words--the lingo I'm using right now has sponged its vocabulary from more than three hundred and fify other languages--explains the way language and history have interacted, and shows how what we say is often deeply affected by social change.

The writing is energetic and cheerful, and the book has a good general index, a thorough bibliography, and a very helpful separate index to individual words and phrases--just made for those who want to dip into rather than immerse themselves in the text.  Some examples: "algebra" comes from the Arabic al-jabr, and it originally meant bone-setting. Think about it: it makes sense.

"Aloof": taken from a Dutch nautical term which meant to steer away from a hazard. I won't tell you about "ambulance" or "zigzag." To go any further would be like giving away plot points in a mystery.