Thomas passed through several local groups in his youth, including the Saints & Sinners and the Ramblers, and also for a time played and sang lead in El Riot & the Rebels, a band whose members included bassist John Lodge and organist Mike Pinder. In 1962, Thomas and Pinder formed the Krew Cats, who made the by-then-standard pilgrimage to Hamburg, Germany, for work. They split up in 1963 after returning to Birmingham, but the two decided to form a new group on the bustling band scene in the city, and the result was the Moody Blues, originally an R&B-based quintet, somewhat close in spirit to the early Rolling Stones, the Animals, and the Pretty Things. The band enjoyed a monster hit with "Go Now" in 1964, but was unable to follow it up, despite some occasionally brilliant efforts (including "From the Bottom of My Heart"). When the group's bassist, Clint Warwick, and guitarist/singer, Denny Laine, departed, it was Thomas' old El Riot bandmate, John Lodge, who came in as the group's new bassist/singer, followed by guitarist/singer Justin Hayward, and a new phase in their history began. As this new edition of the group moved away from R&B-based songs and into more experimental pop sounds, Thomas returned to the flute as his primary instrument, and his voice also soon began getting featured more prominently in their new music. Thomas wasn't as natural a songwriter as Pinder, Lodge, or Hayward, but with Pinder and Hayward's assistance he emerged as an important composer for the group, providing "Another Morning" and the hauntingly beautiful "Twilight Time" to their growing repertoire of new, more adventurous songs, which were captured on the breakthrough album Days of Future Passed (1967). On their next album, In Search of the Lost Chord (1968), Thomas delivered the group's defining psychedelic-era anthem, "Legend of a Mind." With the central phrase "Timothy Leary's dead/Oh no, he's outside, looking in" and its elaborate instrumentation (swooping cellos and droning Mellotron sharing the spotlight with Thomas' flute), the song became a central part of the psychedelic era's ambience, and part of the pop culture "soundtrack" almost as much as the Beatles' "Strawberry Fields Forever" or "Penny Lane"; the fact that it utilized the name of Dr. Timothy Leary, a widely known, once respected academic turned LSD guru, only boosted the group's credibility as a serious psychedelic act within the counterculture of the period.
Thomas' flute was also very prominent in the group's two early psychedelic era hits, "Nights in White Satin" and "Tuesday Afternoon," and his harmony singing could be heard everywhere on their records. Additionally, he and Hayward occasionally generated a memorably beautiful collaborative effort, such as the sublimely gorgeous "Visions of Paradise" from In Search of the Lost Chord. As each member took on a distinct personality in his writing -- Pinder the serious mystic, Hayward the romantic, Lodge the rocker, and drummer Graeme Edge the poet -- Thomas became the band's resident playful mystic, his work characterized by lighthearted songs such as "Dr. Livingston, I Presume," "Dear Diary," and "Nice to Be Here," the latter, a kind of trippy pastoral idyll mixing music and nature images. He also occasionally delivered a serious piece like "Eternity Road" or gentle romantic ballads such as "Our Guessing Game," "And the Tide Rushes In," and "For My Lady." Despite his late start as a composer, Thomas was one of the prominent songwriting voices within the band, and authored more than his share of popular songs in their repertoire.
During the group's hiatus, which lasted from 1974 until 1978, Thomas released a pair of solo albums, From Mighty Oaks and Hopes, Wishes, Dreams. These albums, produced on a sometimes grand scale, presented Thomas' singing but didn't feature his playing, in anticipation of the chance to perform this material in concert. From Mighty Oaks made the top 100 and featured several songs that might have gone well on a Moody Blues album of the period, including the rocking "High Above My Head" and the whimsical, lyrical "I Wish We Could Fly." But none of the members was able to sustain career momentum separate from the context of the group, and by late 1978 they were back together. Thomas' songwriting moved closer to center stage within the group during this period as Mike Pinder chose to leave the band, rather than tour behind the new album, Octave. Thomas was left as the group's resident mystic and cosmic rocker -- nowhere was he more prominent as a songwriter than on Long Distance Voyager (1981) (regarded by many latter-day fans as the band's best post-reunion album), on which a trilogy of his songs, "Painted Smile," "Reflective Smile," and "Veteran Cosmic Rocker," comprised the finale, on record and on-stage for the accompanying tour.
His role in the group receded significantly in the decade after, however, as his songwriting ebbed and his flute was less in evidence in their music. In interviews during this period, Justin Hayward, in particular, went out of his way to praise Thomas' singing and emphasize the importance of his songwriting, Thomas' voice did remain a constant with the group on-stage, and he achieved much greater prominence for a time at the band's orchestra-accompanied concerts -- with a flutist from the orchestra available to play the instrument, he was at last able to sing such numbers as "For My Lady," which he'd never been able to perform live before. Thomas' health declined as the new century began, however; he was unable to join the band on their winter 2003 tour, and was replaced by flutist Norda Mullen. Later that year, after some 40 years' association with the band, Thomas retired from the Moody Blues -- with his departure from the lineup, the group's concert set also lost "Legend of a Mind," which had proved to be one of their most popular live numbers across 35 years. It was also ironic that, because their older songs have tended to dominate the group's popularity even in the 21st century, Thomas and his songs, especially those from the '60s, are still well-represented on any of the various hits and best-of compilations that have appeared in the years since his retirement. ~ Bruce Eder, Rovi