by Scott YanowOf pianist McCoy Tyner's seven Blue Note albums of the 1967-1970 period, Expansions is the most definitive. Tyner's group (comprised of trumpeter Woody Shaw, altoist Gary Bartz, tenor saxophonist Wayne Shorter, Ron Carter on cello, bassist Herbie Lewis, and drummer Freddie Waits) is particularly strong, the compositions (four Tyner originals plus Calvin Massey's "I Thought I'd Let You Know") are challenging, and the musicians seem quite inspired by each other's presence. The stimulating music falls between advanced hard bop and the avant-garde, pushing and pulling at the boundaries of modern mainstream jazz.