You know the Carnegie Institute and the Philadelphia Museum of Art, but have you ever visited the Toy Robot Museum in Adamstown or Bill's Old Bike Barn in Bloomsburg? The Tom Mix Museum in Mix Run? The Houdini Museum in Scranton? Pennsylvania's many small museums are easy to miss in an age of instant information and superhighways. After reading Therese Boyd's guide, however, you'll rush to get off the beaten track to find them. Pennsylvania's little wonders are as entertaining as they are educational.

Unlike large museums, which display masterpieces of art and other "important"...