Cactology is the definitive collection of music from one of the most underrated and overlooked hard rock bands of the '70s. From the opening notes of Howlin' Wolf's "Evil" (cast by Cactus as a Black Sabbath/Led Zeppelin-type monster riff sludge rocker), the listener is swept into a dark world of beer-swilling, testosterone-fueled stud boogie. On the CD's second track, the band gives Mose Allison's lightly swinging jazz/blues classic "Parchman Farm" a hyper-speed freight train treatment that shames even the Who's thunderous Live at Leeds version of Allison's "Young Man." All the while, bassist Tim Bogert and drummer Carmine Appice (both of whom are better-known for their work with Vanilla Fudge and Jeff Beck) add a thunderous, chops-heavy bottom end. This rhythm section is perhaps the most distinctive element of the Cactus sound, a kind of missing link between Cream's Jack Bruce/Ginger Baker tandem and the virtuoso grooves of Rush's Geddy Lee and Neil Peart. Although Cactus never had an actual hit song, Cactology includes all of the band's best-known recorded moments as well as two previously unreleased tracks. The first of the these is the gem, a reworked version of fuzz guitar pioneer Link Wray's "Rumble," entitled "Rumblin' Man." This track must rank among the heaviest music ever recorded prior to the advent of Metallica. A slow, steamroller-like goliath of a song, "Rumblin' Man" sounds like the upset digestive tract of some evil giant. Although this disc makes clear that Cactus lacked the songwriting skills to ever reach a mainstream Top 40 audience, it also gives the band its due as one of the most energetic pure heavy rock ensembles ever to enter a recording studio.