Released in July 1968, The Moody Blues’s second album with its classic line-up (Edge/Hayward/Lodge/Pinder/Thomas) ‘In search of the lost chord’ was in keeping with the zeitgeist. As the world was beset by political assassinations, the Paris and Czech Spring uprisings and indiscriminate bombing in the East one band went internal to make sense of the external.

Following on from 1967’s prog-rock orchitectural ‘Days of Future Passed’ ‘In search …’ is a conceptual perceptual that captures the enlightened spirit that pervaded the pop-cultural air. The quest for deeper meaning meant thinking outside the ordained boxes of society.

Exoticism pervades from the use of Eastern instrumentation and the future-signposting sounds of the Mellotron. Mysticism invades through the philosophical drives to make sense of what is ‘it’ all about?

Where some groups were ‘turning on, tuning in and dropping out’ to the smells of incense and nonsense, groups like the Moodies were more concerned with self-discovery, ‘turning in, tuning on and dropping by’: a harmonic herald to collective harmony.

Paradoxically (or is it?) commencing with ‘Departure’ a mantra-filled intonation that aligns the Establishment’s race for outer space exploration with the need for a deeper understanding of innerspace, its hurried conclusion ushering in the metronomic ‘Ride my see-saw’, a single which bewilderingly didn’t even get into the Top 40. Presaging the space rock antics of Muse, the song is an invitation to accompany ‘me’ on an adventure. The B-side ‘A simple game’ is a standout, a plea to the listener that to ‘see’ is ‘to be free’ and ‘be what you want to be’, scratch beneath the veneer and the mechanics of the system are clear for everyone to view. Free your mind and the best will follow.

‘Dr Livingston, I presume’ challenges prescribed preconceptions, questioning the norms and traditions that were (and still are) expected. ‘We’re all looking for someone’ goes the chorus as further explorers are reeled off ‘Captain Scott … Christopher Columbus’ positing the eternal question ‘what is it you’re looking for and did you find it?

Portals, entrances, walkways are all passages through which to enter other worlds and until you have crossed the threshold then you won’t/don’t know what’s on the other side. ‘House of Four doors’ with its eerie synthesiser and baroque soundscape teases the listener to open up and step through. The vocals at some point are reminiscent of Frankie Valli and the Four Seasons’ doo-wop excitations.

LSD-head Timothy Leary is summonsed from a premature afterlife on ‘Legend of a mind’ a trip of the light fantastic voyage, is death the end or is it the beginning of being ‘outside, looking in’? Pharma-existentialism encapsulated in less than 7 minutes, an unRAVELling bolero.

‘Voices in the sky’ and ‘Visions of paradise’ showcase Hayward’s unique voice: perennially pastoral and spiritually soothing. The former is a communing communion to the higher self, the latter a flute-sitar drenched ode to Edenic emancipation.

‘The Actor’ asks if our everyday existence is simply a rehearsed performance, our self a succession of rehashed scripted representations that we give in order to be acclaimed/accepted: ‘The curtain rises on a scene with someone chanting to be free … the sleeping hours take us by'. Ergo: live the dream.

Overall it’s hard to detect if the group are wryly mocking or spryly rocking the ‘hippy-dippy heavy, maaan’ aspects of the end of the 1960s that has now become go-to shorthand for media-historicising. There’s an almost religious anti-religiosity throughout, more a devotion to pure emotion that will reward the true seeker.

This deluxe format is comprised of new mixes of the album, B sides, John Peel sessions, unreleased footage from French television and a 76-page book with extensive sleeve notes by compiler Mark Powell.

If you haven’t found that chord by the end of this then you’re not looking/hearing hard enough.