A second version saw the genre broaden, with pop artists making forays into more challenging territory, reciprocating the moves that Miles Davis and other jazz pioneers had initiated earlier in the decade.
Steely Dan delivered one of the most sophisticated examples of jazz-rock fusion with 1977 LP Aja. But while the band's central figures, Donald Fagan and Walter Becker, were razor-witted New Yorkers through and through, it was in Los Angeles that they created their best-selling album, and the moderate Californian climate that permeated its grooves.
Fagan and Becker had by now totally shed the limitations of a classic rock band line-up, a process they had begun with 1975 album Katy Lied.
The player credits for Aja would eventually read like a phone book of top-shelf session musicians and soloists, with entire troupes being mixed, matched and picked over to deliver what would sometimes only amount to a few seconds of tape. Most were unsure what, if any, contribution would make the cut.
Guitarist Dean Parks has said that despite appearances, Fagan and Becker's quest was not for perfection but for the stage beyond perfection where the musicians can loosen up and truly inhabit the piece.
Given how seamlessly the album's seven tracks meld R&B, rock, funk and jazz into a quintessentially '70s slice of spit-polished FM silverware, it has to be said that they got what they were looking for.
Peg, Deacon Blues and Josie became radio hits, while the album peaked at No 3 on the US pop charts and became Steely Dan's first platinum seller.
For Fagan and Becker, it marked the peak of their confidence and delivered a payoff for a shared determination to make expansive yet accessible American rock.
