Throughout the Beatles' history, many fans and critics have noted the existence of a "Fifth Beatle" -- from keyboardist Billy Preston (who helped perk up the Let it Be sessions) to producer George Martin, who contributed the occasional keyboard overdub, wrote orchestral arrangements and helped the band achieve its most groundbreaking sonic tricks in the recording studio.

But not all of these arguable "Fifth Beatles" were destined for rock greatness. Most fans are aware of drummer Pete Best and bassist Stuart Sutcliffe, both of whom helped flesh out the lineup during the band's formative stage in the early '60s. But few give historical credit to bassist Chas Newby, who, on Dec. 17, 1960, began his two-week run in the Slightly-Less-Than-Fab Five.

In late 1960, the Beatles returned to Liverpool after a legendary stint in decadent West Germany, but they were one man down. Sutcliffe, who was known more for his mod haircut than his bass skills, had chosen to stay in Hamburg to focus on his art career. Drummer Pete Best recommended 19-year-old Chas Newby, an on-holiday college student who'd formerly played with Best in the Blackjacks.

This quintet (which also featured the core guitar and vocal trio of John Lennon, Paul McCartney and George Harrison) went on to play four gigs in December 1960, the first of which happened on Dec. 17 at Liverpool's Casbah Club. As legend has it, Lennon invited Newby to continue with the band on its second voyage to West Germany; Newby, unimpressed with the measly wages, declined the offer, choosing to pursue his academic career instead.

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Unlike his former bandmates, Newby has largely lived life out of the rock spotlight. After studying chemistry at the college level and eventually obtaining a masters degree in chemical engineering, he settled down into a simple but fulfilling life. He started a family with his late wife, Margaret, and eventually accepted a job as a math teacher at Drotwich High School in Worcestershire.

“Music was never going to be a living for me," Newby told Sunday Mercury in 2012. “I wanted to do chemistry. John, Paul and George -- they just wanted to be musicians." Even though Newby never kept up with his old lads over the years, he fondly recalls his brief stint in the Beatles, particularly his friendship with Harrison. “George was the one I got on the best with," Newby recalled in the interview. "He knew Pete already. He was always telling funny stories about getting deported from Germany whenever we sat around chatting."

Newby, who spends his free time golfing and singing in the Alcester Male Voice Choir, has managed to reunite with his old pal Best for the occasional live gig. Overall, though, he's been perfectly satisfied with his career choices, and he's never regretted turning down Lennon's offer more than 50 years ago. “People sometimes don’t believe me when I say I’ve no regrets,” Newby said. “But I really haven’t. I have enjoyed my life immensely."

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