Book Music is a medium for storing the music played on European mechanical organs. Similar to piano rolls, but book music is made from thick cardboard, containing perforated holes representing the musical notes to be played. The book is a folded zig-zag style. Music rolls were never popular in Europe, except for some German instruments, and book music was the most commonly used medium for large instruments. Book music was used as early as 1863 by Henri Fourneaux in his Pianista.

One of the advantages of book music is, that it can be mechanically interpreted, by having so-called "keys" (levers on springs with an upside down "V"-shaped hook at the end) run underneath the book, which will mechanically open valves, whenever a hole in the book passes by. Paper rolls on the other hand are "key-less" and can only be read by pneumatic pressure or suction. Some mechanical organs, particularly those of German manufacture by firms such as Gbr Bruder and Ruth play keyless cardboard book music, operating pneumatically.

The disadvantage of book music is the size and weight to store music.

The advantage of book music is that it is sturdy and not subject to expansion and contraction with humidity. This allows for large books to be manufactured, allowing musically versatile capabilities.

See also

• Punched card - Book music was originally developed by taping a stack of punched cards together.
• Punched tape
• Player piano