Whereas just about every other genre of the late ’60s and early ’70s is now revered, jazz-rock remains deeply unfashionable. That hasn’t deterred Summers, who has made a string of albums that combine his love of jazz virtuosity with his appreciation of rock dynamics. Earth & Sky is classy, all-instrumental stuff. But it also displays all the reasons why, Pat Metheny apart, jazz-rock fusion has been in the doldrums since the days of McLaughlin and Hancock. The suspicion of showing-off is never far away as tunes get buried in layers of noodling. Music to admire rather than love.