Gangsta Rap (aka G-Funk)
Started on the West Coast with rappers like Ice-T, NWA and Too $hort, but found a Southern counterpart in The Geto Boys. Peaked with the golden age of Death Row. Dr Dre proclaimed gangsta rap dead in 1996. Yet Master P has since brought it back to life with his Louisiana-based No Limit stable, which is also the current home of former Dre protege, Snoop Dogg. Leading exponents now: 2Pac (still), Scarface, Snoop Dogg, E-40, Master P, Silkk The Shocker, C-Murder.

Playa-Rap
The East Coast answer to gangsta rap popularised by Puff Daddy and his New York-based Bad Boy label. The playa is like a gangsta. Playa-rap fuses together R&B or pop samples and hardcore lyrics. The forerunner of this genre is Slick Rick, while the exemplary playa is The Notorious BIG, who was slain in a drive-by death in 1997. His true heir is Jay-Z, although Puffy himself and Ma$e have invested the playa genre with more of a poppy angle (see below). The Wu-Tang Clan's RZA and others hold that Raekwon and Ghostface Killah developed the playa-gangsta role on their 1995 album "Only Built 4 Cuban Linx". Leading exponents now: Jay-Z, Nas Escobar, Lil' Kim, Foxy Brown, Cam'ron.

Hip-Pop
Party rap that borrows heavily from pop or R&B records. This tends to appeal to radio, and so it readily crosses over into the top 40. The leading producers right now in this field are Puffy and the Trackmasters, who 'jack' beats wholesale from old hit records. This genre is more palatable to the ladies. Leading exponents now: LL Cool J, Coolio, Puff Daddy, Ma$e, Wyclef Jean, Pras, Will Smith.

Timbaland
Oddly enough, Timbaland's futuristic funk is yet to be named as a genre, although everyone knows the sound. The Virginian first emerged as a studio protege of Jodeci's DeVante Swing but moved on to make his own mark as a producer. Timbaland usually writes with his homegirl Missy Elliott (she comes up with the melodies and lyrics). While Timbaland's music references electro, T La Rock's Def Jam work and the classic Minneapolis sound of the early 80s, it also features triple drum beats similar to drum Ôn' bass. Timbaland is partial to eccentric sampling -- like baby gurgling. Leading exponents now: Timbaland, Missy Elliott, Ginuwine, Aaliyah, Playa, Nicole.

Alt-Rap
In other words, alternative rap. A name given to conscious, Afro-Centric rap -- which often bears a more musical bent also. First really surfaced in New York with the Native Tongues family -- the Jungle Brothers, De La Soul and A Tribe Called Quest -- as a foil to West Coast gangsta rap, though Rakim and Gang Starr are also leaders. Leading exponents now: Rakim, Gang Starr, Common, Lauryn Hill and the Fugees, The Roots, OutKast.

Jazz-Rap
Rap with a jazz sensibility -- as pioneered by those more cerebral, avant garde hip-hoppers Gang Starr and A Tribe Called Quest, along with the likes of Us 3. It has proved controversial in old skool jazz circles -- Wynton Marsalis continues to diss it, but his brother Branford thinks it's dope. Tellingly, that smart cat Miles Davis was cutting a hip-hop record with East Coast producer Easy Mo Bee ("Doo-Bop" just before his death. Leading exponents now: Branford Marsalis' Buckshot LeFonque, Gang Starr, The Roots.

Underground Hip-Hop
Hip-hop that sticks to its old skool roots and values. Leading exponents now: anything coming out of the Rawkus label, Jurassic 5.

Illbient (aka Turntablism)
Mostly instrumental hip-hop made by those DJs who refer to themselves as 'turntablists'. This has also been identified as a cousin of trip-hop. It was Q-Bert of the Invisibl Skratch Piklz who coined the term 'turntablism'. Leading exponents now: DJ Shadow, Invisibl Skratch Piklz, The X-ecutioners.

Rock-Rap
Basically, rap with rock guitars. Few acts have made a career out of it. Most rock-rap joints are novelty records or one-offs -- like Busta Rhymes' recent hook-up with Ozzy Osborne, "This Means War!!". Usually this genre finds an alternative white audience. Leading exponents now: Run-DMC, Beastie Boys, Rage Against The Machine.

Miami Bass (Miami Booty Music)
Miami derivative of rap that mixes fast beats and full-on rap lyrics about sex, sex and more sex. This style is aimed at the dancefloor but is also jeep-friendly. The godfathers of this genre are the 2 Live Crew. Atlanta's Jermaine Dupri has given Southern booty more of a soulful, crossover element with his So So Def Bass All-Stars compilations. Leading exponents now: So So Def Bass All-Stars (including Inoj), Quad City DJs.

Detroit Bass (Detroit Booty Music)
A mid-western variant of the above -- sometimes with a gritty gangsta vibe. In Detroit, an 80s radio DJ known as The Wizard has been cited as an influence on this style because of his breakneck mixing technique -- the quickmix. He is better known in other parts of the world as the techno guru, Jeff Mills.

New Jack Swing
Teddy Riley created the swing R&B genre -- mixing together street attitude and old skool R&B. Together he and Keith Sweat shaped the first swing hit -- "I Want Her" -- over a decade ago. While this style has found a slick British counterpart, it has gradually been superseded by hip-hop soul in the US. Leading exponents now: BLACKstreet, Keith Sweat, Another Level.

Hip-Hop Soul (aka Street-Soul)
The Force MDs may be the originators, but Puff Daddy gave hip-hop-soul a name a decade or so later. Puff combined hip-hop beats (often sample-based) and R&B vocals on his early production for Mary J Blige. DeVante Swing did something similar with his group Jodeci, whom Puff also guided early on. Leading exponents now: Mary J Blige, TLC, Usher, 112, Total, Allure, Brandy, Monica.

Classic 90s R&B
An update of the classic 80s soul and R&B sound that is more selective in its use of hip-hop elements. Often bears a resemblance to the 80s' Quiet Storm style of, say, Anita Baker. Leading exponents now: Boyz II Men, R Kelly, Sparkle, Toni Braxton, Faith Evans, Kelly Price.

Pop-Soul
Pop ballads sung by divas with soulful vocals who can pull off a lot of acrobatics. Leading exponents now: Whitney Houston, Mariah Carey, Toni Braxton, Deborah Cox, Puff Johnson.

Nu-Soul
Essentially an in vogue R&B style that references the classic soul of the past. Real instrumentation meets hip-hop beats and contemporary, often culturally conscious, lyrics. Leading exponents now: Me'Shell Ndegeocello, D'Angelo, Maxwell, Lauryn Hill, Erykah Badu, Eric Benet.

Street Gospel
Gospel continues to exert a profound influence on 90s genres as far removed as speed garage, garage, house, R&B and hip-hop soul. Kirk Franklin has taken gospel back to the streets, making it sound closer to secular, hip-hop-inflected R&B. His is kinda like gospel with attitude.