Guitarists whose playing is truly unique and identifiable are few and far between.  Sure, you can maybe listen to two seconds of a solo and know who’s playing it and what song it’s off of, but what if it were a new song?  Eddie Van Halen?  Sure.  Brian May?  Maybe.  If Hendrix and Stevie Ray Vaughn were alive I’d throw them into the mix.  But one person truly deserving of being in that conversation is the late, great Allan Holdsworth, whose virtuosity on the instrument is matched by his unique way of using harmony to construct massively complex chord structures that delicately balance straight jazz, fusion, and pop.  I.O.U. stands out as a masterpiece that recalls the best of what Holdsworth brought to music, still vibrantly alive almost 40 years after it was recorded.