Rap lyrics pop into our heads at inappropriate times, end up as our yearbook quotes, and work their way into our everyday conversations. But very few bars would be as memorable if not for the music that accompanies them.

Great production can make even the most objectionable or cheesy lyrics sound great. The producers who create these beats may not be as glamorous as the rappers who spit over them (at least, most of the time), but they are equally important. Thus, they are equally subject to hip-hop’s sixth element: making lists.

Back in 2015, we chose The Best Rapper Alive, Every Year Since 1979. It was an exhaustive list inspired by a simple idea: a new way to take on the inevitable Top 5/GOAT discussions that dominate the hip-hop conversation. Instead of making the list about how someone stacks up against the entire canon of hip-hop, we narrowed in on who, in any given year, was unbeatable. From Grandmaster Caz in 1979 to Kendrick Lamar in 2017, we chose who had the alchemical combination of quality, momentum, and historical importance at every moment in the genre’s development.

It was only fitting to extend this concept to producers, as well. Producers are, in the words of the old Maoist slogan, holding up half the sky—giving rappers a sonic canvas on which to paint their pictures. Great producers, like rappers, have specific moments when they’re controlling the game, making classics, and setting trends seemingly at will.

A few notes before we begin: Being the BPA in a given year doesn’t mean that you’re the best producer, in whatever qualitative way one might decide these things. All-time greats like DJ Premier, Diamond D, Just Blaze, and Pete Rock—GOAT-level producers by any measure—don’t win a single year. It’s not because they’re not great. It’s that, during any given 12 months, there was always someone who edged them out, either due to volume of standout work (see DJ Quik’s astounding 1991, with four albums that paved the way for West Coast dominance to come); or to influence (in 1992, Dre delivered The Chronic—an album that gives him the prize as he faced perhaps the stiffest competition of any year on this list); or to ushering in a sound that was all of a sudden everywhere, all the time, and came to define its era (take one look at Lil Jon’s 2003 output and try not to imagine yourself in the middle of a Chappelle skit).

So, what exactly does it mean to be a producer? The term has meant different things to different people in different eras. In the early years of rap, it was often the person who paid for the studio time or, alternately, the person who wrote and arranged the music. Sometimes it was the person whose name was on the record, or the record contract. Other times, it was the mad genius who searched through endless records for the perfect beat, or the collective that spent months in the studio side by side. Today, it most frequently means someone who composes a ton of music and shares their signature sound (and producer tag) with a variety of artists. We tried our best to account for all meanings of the word in the list you’re about to read.

This list is meant to spark debate (we know you’ll tell us where you think we got it wrong) and to give credit to the people who inspire us to dance and nod our heads to the beat. Most of all, it’s meant to compel you to go back and (re)discover some of the most exciting, moving, challenging, ubiquitous, and important music of the last four decades. Enjoy.

Illustrations by Sho Hanafusa