Windham Hill initially gained a sterling reputation through exquisitely recorded and played instrumental guitar albums. The label now commemorates 25 years of recording by picking the cream of its crop. A great harvest it is, too! Founder Will Ackerman rerecords the early "The Impeding Death of the Virgin Spirit." Then there's Alex De Grassi's gentle pyrotechnics and Doyle Dykes's jazzy inflections. Together, they've truly expanded the boundaries of acoustic-guitar playing--an effort that may have reached its zenith with the late Michael Hedges. His "Aerial Boundaries" remains a tour de force, while his live duet with bassist Michael Manring--"Rikki's Shuffle"--shows the synergy between two great musicians. --Chris Nickson