"The Moody Blues - In Search of the Lost Chord" is a seminal album released in 1968, representing a key part of the British rock band's exploration into progressive and psychedelic rock. The album is known for its thematic coherence around the concept of a quest for spiritual fulfillment and broad musical experimentation that includes the use of diverse instruments such as the Mellotron, sitar, and tabla, which were somewhat unconventional in rock music at the time. Tracks like "Legend of a Mind," which famously references LSD advocate Timothy Leary, and "The Actor," a mellower, more introspective song, highlight the album's range in both lyrical and musical complexity. The album also includes "Ride My See-Saw," which became one of the band's most popular and enduring concert numbers.