Ready to Die turns 20 on Saturday, and even at a moment when hip-hop is particularly taken with such milestones, this is (fittingly) an enormous one. Ready to Die is not the greatest rap album ever made, and probably isn’t even the greatest rap album made in 1994—it sags at times with superfluous skits, some of its production touches have aged awkwardly (congrats to that whistling synth hook on “Big Poppa” for owing 20 years’ worth of royalties to The Chronic), and Sean Combs’ somnambulant hype-man routine only grows more irritating with time.

But it is quite possibly the most important, if only for the reason that its maker transformed the music like no rapper before or since. Biggie Smalls didn’t alter the hip-hop landscape so much as crater it, leaving behind an unfillable void and an unhealable wound. The Notorious B.I.G. is the greatest rapper who ever lived in the same way that Michael Jordan is the greatest basketball player who ever lived: Some people may argue but they are usually Luddite classicists, incorrigible homers, or hipster contrarians. Seventeen years after his murder at the age of 24, he is of a piece with Miles, Dylan, the Beatles, Aretha, artists whose influence is so immense it ascends into a sort of fundamental sonic iconography, the never-ending soundtrack to everything. A world without KRS-One or Ice Cube or Jay Z would be unimaginably impoverished, but a world without Biggie Smalls is simply unimaginable.