A while back the Official Wife of Zooglobble brought this book home from her preschool classroom. It's called What Instrument Is This?, and as you might deduce from the title, its structure is a series of questions encouraging the elementary-school-aged reader to guess the name of an instrument.
Now, given that the book is 20 years old, and some of the pictures inside appear to be at least twice that, one could be forgiven for dismissing the book. But it's a totally charming book, probably the best "introduction to instruments" book I've ever seen.
Author Rosemarie Hausherr organizes the instruments by instrument group (winds, strings, keyboard, and percussion), and features many different types of pictures and settings. There's just enough detail to make it interesting without overwhelming -- the recorder is a long, hollow piece of wood with eight holes, played by blowing into the whistle mouthpiece, with a "warm and cheerful sound."
While the text style and the design of the book remain remarkably consistent throughout (and the subtle logos representing each of the four instrument groups would look modern today), that's offset by the diversity of musical and photographic styles and subjects. Classical music, sure, but bagpipes? CBGB (yes, that CBGB) is thanked in the credits, so I can only assume the picture for the electric guitar (strings section) is from a gig there. The kids in the pictures reflect a fairly diverse crowd, spanning many races and featuring more than one child with disabilities playing (or experimenting with) instruments. It's nothing fancy, but it's great at keeping kids interested without trying too hard to do so.
The book appears to be long out of print, but Amazon has several copies for little more than the cost of shipping and I'm sure it's available elsewhere. (That's an Amazon affiliate link, by the way.)
What Instrument Is This? is a great book for preschool and elementary school classrooms, as well as families looking to introduce a visual element of music into their homes. Definitely recommended.