There's little argument that the quintet Miles Davis led between 1965 and 1968 was one of the classic combos in the history of jazz. By teaming with the adventurous young musicians Wayne Shorter (tenor sax), Herbie Hancock (piano), Ron Carter (bass), and Tony Williams (drums), Davis pushed mainstream jazz toward the avant-garde, expanding on the modal jazz he inaugurated with Kind of Blue and laid the groundwork for fusion. Four of their five studio albums -- ESP, Miles Smiles, Sorcerer, Nefertiti -- were essential, and even when they were slightly off the mark, as on Miles in the Sky, they were still filled with provocative sounds and ideas. That's the reason why The Miles Davis Quintet 1965-'68: The Complete Columbia Studio Recordings is an essential release. It contains all the music from each of the five studio records, plus half of the material released on Filles De Kilimanjaro and Water Babies, as well as several alternate takes and 13 previously unreleased selections. There's no question that this material is necessary for any jazz collection, but this may not necessarily be the best way to acquire it. The strict chronological sequencing is according to session order, which means the sequencing of the original albums -- which was quite effective in conveying the combo's ideas -- is thrown out of line, and the long stretches where alternates and master takes are back to back may be tedious to some listeners. Also, packaging all the discs within cardboard mock-record sleeves in a bound booklet may look attractive, but it's impractical and not designed for heavy listening. In other words, this music is essential, and this set will appeal to most serious jazz fans and historians, but less dedicated listeners are better served by the original albums.