Death has boosted the careers of many artists. But it's especially effective for rap stars, for whom dying, as a career move, usually ranks just below hiring Dr. Dre as a producer or getting Eminem to record a guest appearance. Given the public's voracious appetite for music by slain rappers, it's not surprising that Death Row continues to release posthumous 2Pac albums at a rapid clip. The latest is Until The End Of Time, a double-disc set with a title explaining just how long label kingpin Suge Knight plans to exploit Tupac Shakur's legacy. Never rigorous about quality control, 2Pac was legendarily prolific and a ridiculously fast worker, often writing songs in less than half an hour. He also had an unfortunate, perhaps interrelated tendency to lapse into self-parody at regular intervals, as End Of Time song titles like "Thug N U Thug N Me," "When Thugz Cry," and "Fuckin Wit The Wrong Nigga" readily attest. Like Still I Rise, another collection of posthumous 2Pac recordings, End Of Time devotes roughly equal time to the different, often clashing aspects of 2Pac's multi-faceted persona. Tracks like "Let Em Have It" and "Why U Turn On Me" revel in the double-fisted aggression of 2Pac the super-thug, while others, like "Letter 2 My Unborn," explore the more sober, introspective sides of his psyche. Nothing here quite matches the sheer awfulness of its title track and first single, which inexplicably samples Mr. Mister's "Broken Wings," but the album is uneven throughout, perhaps inevitably, given its two-hours-plus length. 2Pac appears to be functioning on auto-pilot throughout many of these recordings, but even when phoning it in, he was still exponentially better than most of his peers. Endangered Species, the first posthumous album from Big Pun, collects Pun's hits, guest appearances, and a smattering of unreleased material in a 24-track compilation clocking in at nearly 75 minutes. Like 2Pac, Pun was prolific to the point of carelessness: In a puzzling tribute during which he also discusses Pun's frequent extramarital activities, rapper Noreaga mentions that Pun would rap on other people's albums even if he didn't like their work. That eagerness to rap with anyone, anywhere ultimately works to the album's disadvantage. For every essential Pun track, like The Beatnuts' "Off The Books" and the super-lyrical "Fantastic Four," the album contains two or three tracks like "Banned From TV"—generic and forgettable gangsta-rap redeemed only slightly by Pun's larger-than-life presence. In a way, Endangered Species captures Big Pun the artist too well, displaying not just the vitality and charisma that made him a superstar, but also the familiar subject matter and frequently sub-par beats that made him so frustratingly erratic.