by Scott Yanow 　　This set from the 1977 Montreux Jazz Festival was very much a spontaneous jam session. Flugelhornist Clark Terry, who happened to be in town early, was added to vibraphonist Milt Jackson's group at the last moment. When players the caliber of Terry, tenor saxophonist Eddie "Lockjaw" Davis, pianist Monty Alexander, bassist Ray Brown, drummer Jimmie Smith and Jackson get together, one does not have to worry about the lack of rehearsal time. The sextet romps happily through Brown's "Slippery," "A Beautiful Friendship," "Mean to Me," "You Are My Sunshine," the CD's bonus cut "That's The Way It Is" and "C.M.J."; both Terry and Jackson have humorous vocals on the latter.