Secret Chiefs 3's first three studio albums were not exactly stripped-down affairs, but Book of Horizons is by far an ambitious release. The first volume of a planned three-part series of albums, Horizons is set up to resemble a compilation of bands, the catch being that all of these bands are headed by SC3 leader Trey Spruance. The six bands, which have two or three songs each on this album, encompass pretty much the full range of SC3's previous stylistic forays, including the funeral ballads and marches of the Forms; the orchestral, Persian-themed rock hybrids of Ishraqiyun; the time-traveling surf-rock of UR; the electro-acoustic collages of Electromagnetic Azoth; the extreme death metal band Holy Vehm; and the sweeping film music homages of Traditionalists…