The Optical Music Series is a set of CDs by the English Neoclassical duo In The Nursery, released under their own ITN Corporation record label. These CDs are meant as companions to several classic silent films of the early 20th century. The series began in 1996 with the release of The Cabinet of Dr Caligari. The most recent release is the 2008 soundtrack to Carl Theodor Dreyer's The Passion of Joan of Arc.