The same Don Ellis that made the jazz world sit-up in the mid-1960s and 1970s with a big band that debuted on the Pacific Jazz label before being signed to Columbia by John Hammond did not leap into the jazz world a fully formed bandleader. He had first served a substantial apprenticeship learning his craft working with several name big bands and had recorded with Charles Mingus while developing a reputation as an experimenter, as How Time Passes reveals. At a time when the avant-garde was preoccupied with free form improvisation, Ellis was experimenting with unorthodox time signatures, 12-tone rows/serial techniques, atonality and freedom within form. The direction of his musical enquiries during this period might be summed up by ‘Improvisational Suite No.1’, which by formal means – the use of the aforementioned techniques – with duetting between Byard on alto and Ellis, reminds the listener of the wholly improvised duets between Ornette Coleman and Don Cherry. Tempo and meter were also not safe from Ellis’ curiosity as ‘How Time Passes’ demonstrates. By 1961, Ellis was being dubbed ‘an ultra-modernist’ by The New York Times, and not without good reason as New Ideas shows, with Ellis now inspired by the techniques of John Cage, the use of canon and again, unusual time signatures. Jazz Jamboree is by contrast a less formal affair, with Ellis accompanied by the Wojciech Karolak Trio then active on the Warsaw jazz scene. Karolak later became a formidable exponent of the Hammond B3 on the R&B circuit, but here emerges as a competent pianist together with Roman Dylag on bass and Andrzej Dabrowski on drums. Both Dylag and Dabrowski had played with Krzysztof Komeda and both would also go on to back numerous name American musicians after Ellis, who contributes a highly professional performance that includes versions of ‘What Is This Thing Called Love?’, ‘Now's the Time’, and ‘Lover’ that simply served to show what an accomplished and wide ranging musician he was. As a result of this performance he would later say he was inundated by offers of work in Europe.