This is the first work of Herbie Hancock's in which his inherently experimental writing style worked on every level. Seeing the limitations that the trumpet had in playing certain styles, he eschewed them by writing the trumpet's (or in this case, the cornet, played by the ineffable Freddie Hubbard) parts very fluidly; part written and part improvisation, similar to how he wrote for the piano on his last album. What follows is one of the most delicate, deliberate, and decidedly minimal mixtures of hard/post-bop, in certain spots having a lean towards the modal. The first two tracks here are passionate and strong hard bop numbers, though the end of "Oliloqui Valley" switches to post-bop. A famously funky number comes through with "Cantaloupe Island", one of Hancock's most revered songs, before the album closes with "The Egg", a lengthy-yet-minimal track that combines hard/post-bop/modal into a beautifully meticulous sound. Truly then, Empyrean Isles was the first fully realized work of jazz's next great genius.