I.O.U. was not the first glimpse of what Allan Holdsworth could unleash on the guitar, but it was his proper debut as a leader, not counting the unauthorized Velvet Darkness from 1976. The mysterious guitar hero from Bradford, West Yorkshire—vocally championed by Eddie Van Halen—had made a splash with The New Tony Williams Lifetime, as well with as prog-rockers Gong, Soft Machine, U.K., and Bill Bruford, among others. It made sense, then, for I.O.U.—which functions as both an album title and a band name—to include a vocalist: Paul Williams, Holdsworth’s mate from the short-lived prog-rock outfit Tempest, and a former member of John Mayall’s Bluesbreakers. Williams sings on four tracks, augmenting a killer trio that also features bassist Paul Carmichael and drummer Gary Husband. Released in 1982, I.O.U. includes a group of instrumentals—"Where is One,” “Letters of Marque,” and “Shallow Sea”—that would remain in Holdsworth’s repertoire for decades. “Temporary Fault,” meanwhile, features Holdsworth on violin; the resulting sound is unlike the SynthAxe he’d incorporate a few years later. And the leadoff track, “The Things You See (When You Haven’t Got Your Gun),” is actually an amalgam of two pieces from a little-known 1980 duo project with pianist Gordon Beck: “The Things You See” and “At the Edge” (Holdsworth himself sings on the latter, sounding a bit like Paul Williams). To hear the I.O.U. version is to look into Holdsworth’s compositional notebook. The sound of the recording is excellent, and not in the least dated. Holdsworth puts forth—most explicitly on “Where is One”—a kind of three-level approach to the instrument: Clean chordal passages with precise right-hand articulation; smeary abstract swells of volume and harmonic color played out of tempo; and that gripping lead-guitar sound, raw and overdriven, consistently reaching beyond what is technically possible—all of it in pursuit of beauty. I.O.U. is timeless brilliance.