The success of the band's previous record, Days of Future Passed allowed the group additional studio time and creative flexibility in crafting a follow-up album.

At the time, keyboardist Mike Pinder told the Melody Maker, "Albums give us a chance to experiment with new ideas.

The songs of In Search of the Lost Chord form a loose concept around a theme of quest and discovery, including both world exploration and inner self-realization.

Justin Hayward acknowledged the influence of psychedelic drugs on the band's creative process: "Oh, we all dabbled in all sorts of things.

"[5] Hayward elaborated on the band's spirit of curiosity and quest for knowledge: "Myself, Pinder and Ray were dabbling in everything, trying to guzzle as much spiritual and psychedelic information as we could possibly get.

We met Timothy Leary in 1968 on our first tour of America, me Mike and Ray stayed with him on his ranch for a week or so, and we had a wonderful time.

John Lodge explains the inspiration for its lyrics: "That song was about the freedom which I felt I'd received, both personally and as part of The Moody Blues.

"[8] The verses recount the journeys of David Livingstone, Robert Falcon Scott and Christopher Columbus, and question whether each explorer found fulfillment in their respective searches.

We were using a lot of phrases of the time, extracts from the Tibetan Book of the Dead, talking about the astral plane and so forth, and it's a reflection of that.

But 'Legend of a Mind' is very tongue-in-cheek because I saw the astral plane as like a psychedelically painted biplane which the hippies hired for a trip around the San Francisco Bay.

[16] The lyrics of the latter song question if experience is just "light passing by on a screen", suggesting that if our perception of life is really just an illusion, then meditation can help us understand the true nature of existence.

[8] In an interview, Hayward remembered the context that inspired the lyrics to "The Actor": "Late at night, the road outside in Bayswater, quiet for a while, all alone in the world (for a bit), being in love but struggling with relationships.

[21] The surprise success of Days of Future Passed gave the group new clout with their record label and artistic freedom in the studio.

Hayward remembered, "We were also fortunate to be with a record company, Decca, who were old music men, a lot of the time making radar systems, who were technically superb with a brilliant studio and staff in West Hampstead.

"[22] One area where the group capitalized on the success of Days of Future Passed was by continuing to employ creative song structures that didn't fit the typical mold of the time.

What sound we couldn't reproduce on stage with orchestration we realized we could do with vocals, so we could take over a lot of the things and do them with the harmonies.

"[27] In the album's liner notes, producer Tony Clarke poetically describes the setting of the album's recording sessions, and the large variety of instruments employed: It's as dark as a tomb!, shadows appear from nowhere, great long arms reach upward into the gloom, and sinister coiled shapes lurk in every corner – even the walls seem to hold their breath.

High up near the ceiling a soft light casts an eerie glow on upturned faces and all around, strange sounding music.

The studio floor resembles a museum for musical instruments, since in this album every single note, beat, or word is performed by the Moodies themselves.

[19]With the album, the group aspired to make the most of both the broad range of instrumentation and Decca's stereo recording technology.

John Lodge remembers: "Once we fully understood what stereo was after listening to what other people did with it, we decided we wanted to have a real panorama for In Search of the Lost Chord where the music would come across as a complete picture.

We worked really hard with that stereo mix to give you a really full experience of sound as if a satellite were spinning around your head.

"[28] "The Best Way to Travel" makes use of newly installed pan pots on Decca Studios' custom-built four-track recording console.

[8] Travers recounted: "I spent two years at Decca, working on album sleeves, then got a job in a design office down in Wimbledon.

I was then contacted by someone I knew at Decca who said the Moody Blues manager liked an illustration of mine and wanted me to meet the band to discuss doing the sleeve for their new album.

I remember on the final pencil rough I showed the band, instead of the skull I had a big padlock and chain which represented the physical ties we all have.

[41]In November 2018, the album was reissued as a five-disc In Search of the Lost Chord - 50th Anniversary Box Deluxe Edition set.

[8] Lodge remembered, It was a time of social change and upheaval, but it was during the era when Alexander Dubcek was in power, and everything had become a lot more relaxed.

We arrived in the country as rock stars and left in the back of a Red Crescent emergency aid plane – that was a reality check.

"[31] Hayward recounted the lasting impact their first American tour had on the band's success: "We're big in the industrial, working-class parts of America.