Glascock had come to the attention of Tull's frontman and founder, Ian Anderson, whilst he was playing bass for the Flamenco-Rock band Carmen.
Carmen were touring as support for Jethro Tull during their "War Child" tour in 1975 and shortly afterwards he joined them as bassist replacing previous incumbent Jeffrey Hammond-Hammond.
Tull were a prolific band with a history of recording and live performance successes under their belt and this was a significant appointment for Glascock.
Although it could be said that the band was passed its prime by the time Glascock joined he still went on to play on the albums "Too Old to Rock 'n' Roll: Too Young to Die!," "Songs from the Wood," "Heavy Horses, Live - Bursting Out," and some of "Stormwatch" - the album Tull was working on at the time of John's departure from the band due to ill health in 1979.
Soon after, on 17th November 1979, John died, in London, as a result of a heart condition that had been exacerbated by an infection. He was only 28.
RockBottoms Recommended Reading
"Jethro Tull": A History of the Band 1968-2001 (Paperback)
This book is expensive @ £33.73 but it is very comprehensive and is probably essential reading for true Tull fans. There is good news, however, for those who would like a book about the band with a less challenging price tag because "Minstrels In The Gallery - A History of Jethro Tull" by Martin Rees is available as a Kindle edition for only £8.04 using the link below.
See the Celebrated RockBottoms Store for more Jethro Tull selected items.