Unit Structures, through its use of two bassists (Henry Grimes and Alan Silva) and the two-reed front of Ken McIntyre and Taylor-mainstay Jimmy Lyons, suggests a "double band." Yet such structures become almost meaningless in Taylor's world: it is all about energy and exploration. Punctuated by percussive bursts and melodic eruptions, Unit Structures is, despite its title, impressionistic and whimsical, although devoid of all standard structures and romance. Instead, Taylor pushes his band to explore the limits of improvisation where nothing--neither form, nor melody, nor structure--is a given. Still challenging listening after nearly four decades. ( Fred Goodman )