In addition to the six hundred fifty pictures and illustrations, there are capsule histories of many of the companies which produced these instruments on both sides of the Atlantic Ocean. There are numerous informative articles on such subjects as arranging piano rolls, how to decode an unknown scale, how "nickelodeon" rolls were originally made, selecting the type of roll to be used for a new orchestrion, arranging music for barrel organs, tuning antique instruments, how rolls are perforated and detailed pictorial tours of both the QRS and Play-Rite Music Roll factories as they manufactured rolls in the early 1980s. There's a good bit of information on player pipe organs, and for the carousel buffs, a fascinating collection of pictures of Charles Looff, the carousel builder, and many of the fine machines he made—all of which were fitted with beautiful mechanical organs.