Like D.C. punk and Detroit techno, Houston hip-hop has influenced musicians across decades, casting a net far broader than a single cluster of urban area codes. Maybe when somebody says "Houston rap" the only things you think of are purple drank, candy-colored low-riders ("slabs"), and the words "chopped and screwed," but the hip-hop scene in Texas's largest city has been a distinctive presence on the national stage since at least the early 90s. And since the mid-aughts it's been all over the charts thanks to the likes of Paul Wall, Scarface from the Geto Boys, Chamillionaire, Devin the Dude, and UGK. It's reached across oceans too: this summer UK rapper Dizzee Rascal released a song called "H-Town" that features Bun B of UGK and fellow Houston veteran Trae the Truth.

Of course H-Town has also touched Chicago. In the late 90s the Geto Boys' label, Rap-a-Lot Records, released music from Do or Die, one of the most important rap groups in Windy City history. And the legacy of the Geto Boys' pioneering gangsta rap makes itself felt in the dead-eyed, brutally narcissistic street-life rhymes of Chief Keef, Fredo Santana, and other drill MCs. UGK have clearly influenced Kanye West, coloring his music with the particular way they drawled their lyrics and deployed their samples of soul and R&B—and at the BET Hip-Hop Awards in 2007, when West took the stage to accept the Video of the Year prize for "Stronger," he gave it to UGK on the spot for "International Players Anthem (I Choose You)." "I've been waiting for the opportunity to win an award that I felt like I shouldn't win so I could tell y'all that," he said. "Really, this is just my opinion, that I'm just a fan."

Most influential of all—and most tightly linked to the Houston sound in the minds of fans—is the late DJ Screw. Beginning in the early 90s, he perfected the dragging, slowed-down chopped-and-screwed sound on literally hundreds of informal releases, and the style's viscous, underwater feel has become synonymous with purple drank—aka "lean," which is usually a mixture of Sprite and prescription cough syrup containing promethazine and codeine. Since Screw's death in 2000, a huge chopped-and-screwed remix culture has emerged, cranking out syrupy versions of popular studio albums and mixtapes (I recently found one of Chance the Rapper's Acid Rap). Seattle MCs such as Nacho Picasso and Key Nyata use a subterranean Screw-inspired sound, as do Miami rapper SpaceGhostPurrp and his Raider Klan crew. The chopped-and-screwed aesthetic has seeped into nonrap genres (vaporwave, witch house) and popped up in Chicago footwork music—on a couple tracks from his new Double Cup, footwork mastermind DJ Rashad seems to be reimagining the ordinarily frenetic dance style with DJ Screw in mind, right down to a vocal hook that refers to his favorite purple concoction. Screw's influence can be felt even at the very top of the Billboard charts: Drake's "Own It," from the recent Nothing Was the Same, begins with spacey ambience and a slowed-down Wu-Tang sample.

As Houston hip-hop's stature has grown, so has its mystique—and the resulting curiosity about what these artists are "really" like is a huge part of the reason the new photo book Houston Rap (Sinecure) exists. It reunites editor Johan Kugelberg and photographer Peter Beste, who documented Norway's insular black-metal scene with the 2008 Vice book True Norwegian Black Metal. Beste spent seven months cozying up to corpse­painted Norwegians for TNBM, but Houston Rap took him nine years to make—and at least some of the photos in the latter are correspondingly more casual and intimate. Lance Scott Walker, a writer from nearby Galveston who collaborated with Beste on a 2007 VBS.tv documentary called Screwed in Houston, wrote the book's text, which includes lots of oral history and a Houston rap timeline. Bun B provided an introduction, and because he's such a respected ambassador of the Houston scene, his name on the cover is as powerful a cosign as Beste and Walker could've hoped for.

Walker interviewed rappers and DJs, of course, but also radio personalities, pimps, ministers, label honchos, strippers, and others; Houston Rap is nearly 300 pages long, and for a photo book it's heavy on the text, with no pictures at all on some spreads. The fact that so many people were willing to talk—and that some of them were willing to be candid about their own criminal misdeeds, or to carry on unapologetically about whacked-out conspiracy theories—suggests that Walker and Beste knew how to earn their subjects' trust.

The quotes are edited into a sequence of excerpts and presented without commentary, a structure that gives Houston Rap a conversational tone—though it often reads like these folks have been talking for a while already, long enough to get deep into the weeds. To keep up, it helps to have at least some knowledge of the slang, hip-hop history, and local characters in Houston—Corey Blount, for instance, helped make slab culture what it is, hitting the clubs with two buddies and three of his tricked-out cars. (Sometimes he'd never even go inside.) Even with the timeline it can be difficult to get a handle on the chronology, because the only info Walker provides with the quotes is the name of each speaker. A map of Houston would've been helpful too, since "Third Ward" and "Fifth Ward" don't even give you the tiny leg up that "south side" and "west side" do in Chicago.

About half the content in the book is organized according to loose themes: prison, strip clubs, pimps, marginalized women, and even specific artists such Hawk, a member of DJ Screw's Screwed Up Click who was murdered while Houston Rap was being made. The pictures don't have captions, except in a numbered list at the back of the book, and the quotes sometimes mention different people than the photos depict. But the combination usually works, even though you might have to keep flipping over to that list to figure out who you're looking at. The section about the rise of slabs and the adoption of Screw's leaned-out music as that scene's soundtrack is accompanied by a photo of ocean-blue cars. Another section is dedicated to Screw's death and the rise of drank abuse, and it's paired with a photo of Screwed Up Click member E.S.G. making dirty Sprite, his eyes fixed on a bottle of cough syrup he's holding high.

That photo of E.S.G. is the closest Houston Rap gets to exploitation. Lean has become widespread in rap scenes nationwide, despite well-traveled stories attesting to its health risks; Lil Wayne struggled with drank addiction for years, and according to Screw's autopsy report his death was due to "codeine overdose with mixed drug intoxication" (though Houston Rap blames complications related to his heart trouble). Despite E.S.G.'s goofy grin, the photo looks almost creepy, and it's definitely raw—but it's easy to sympathize with Beste's dilemma, since making drug users look glamorous is hardly a better solution to the problem of how to portray them.

For the most part, though, Houston Rap follows through on its implied promise to go deep and be honest and avoid cheap cliches, even when it flirts with imagery that could easily be presented stereotypically. The way Beste frames a candid photo of Paul Wall flashing his grill turns it into something much more casual and mundane than the usual in-your-face grill shot: only part of Wall's face is visible, reflected in the rearview mirror of his Cadillac as he drives. Beste also skirts the depressing "rappers in prison" trope with his portrait of Street Military rapper Pharoah, who's serving a 50-year term for aggravated kidnapping; it's so tightly cropped that you wouldn't know he's in jail, unless you notice that the blurry, translucent circles in the foreground are out-of-focus speaking holes in a glass visiting-room barrier. A photo of Scarface wincing while getting fixed up in a barbershop becomes funny by puncturing his mystique—in 1992, when the Geto Boys were in their prime, Reader critic Bill Wyman called them "the most unredeemedly revolting rap act in the country," and he was hardly the only one to see the group as monstrous.

Houston Rap also includes a respectful photo of DJ Screw's father, Robert Davis Sr. (aka Papa Screw), sitting in front of a huge airbrush-style painting of his son. Screw looks almost like an angel in heaven, his bright white shirt fading into the clouds around him. He died years before Beste began working on this book, but his presence in it is huge. Everyone who talks about Screw (and lots of people do) seems to love him—though his friends saw him as larger than life, he never acted too big for them. They reminisce about how Screw copied and sold cassettes by hand, how he'd get in a freestyling rapper's face to see if he was genuine, and how his family was evicted four times because of all the noise he'd make hosting a steady stream of collaborators and buddies. The stories and photos aren't always rosy or flattering, but they pull off what Houston Rap as a whole is trying to do: display dimensions of these artists and their community that can be hard to see in the shadow of their legends.