"What is a N.E.R.D? N.E.R.D stands for No One Ever Really Dies. The Neptunes are who we are and N.E.R.D is what we do. It's our life. N.E.R.D is just a basic belief, man. People's energies are made of their souls. When you die, that energy may disperse but it isn't destroyed. Energy cannot be destroyed. It can manifest in a different way but even then it's like their souls are going somewhere. If it's going to heaven or hell or even if it's going into a fog or somewhere in the atmosphere to lurk unbeknownst to itself, it's going somewhere." – Pharrell Williams
Pharrell Williams and Chad Hugo of The Neptunes are the most revolutionary production tandem in modern music since Quincy Jones and Rod Tempterton put down shuffle-beats and doo-wops behind a young singer named Michael Jackson. With their digital musical palette and vivid imaginations, they've taken their hip-hop foundation and un-tethered the bounds of pop, bestowing unsuspecting hit records in almost machine-gun-like succession – whether in rap (Jay-Z, Busta Rhymes, et al), R&B (Usher, Babyface), pop (Britney Spears, Justin Timberlake) or rock (No Doubt).

But N.E.R.D is not the Neptunes. N.E.R.D is the offspring of the Neptunes id, a fly-or-die, thrash-around, do-as-you-will, set-your-soul-on-fire alter-ego that subscribes to no rules, adheres to no agenda. It is Pharrell, Chad and Shay – a trio whose chemistry allows the uninhibited exploration of the sounds, emotions and impulses of self and society, of identity and belonging. Of life.

Fly or Die is the second album from N.E.R.D, picking up where the groups debut, In Search Of…, left off. "It's evolution, for real," says Shay. "There's an entire dimension to music and life that we touched on with In Search Of…, but that was only the beginning. Those were only doors to this other dimension and with this album we are there."

From a musical perspective, Fly or Die, picks up on the free-wheeling sensibility of its predecessor. The most underappreciated aspect of The Neptunes' Midas touch is the melody and carefully crafted songwriting inherent in their barrage of hits – the complexity is in the simplicity. The songs of Fly or Die represent the spectrum of influence impressed upon the trio, from classic rock and Beatles-esque pop to old funk and new wave. It's the space where musical styles are truly influences – not reflexive actions.

"I think we learned a lot from the first album and we've opened up more here," explains Chad. "I think we're going places we haven't gone before."

Originally, In Search Of… was painted through the familiar digital colors that marked Neptunes-produced songs for other artists. Closer inspection indicated that if N.E.R.D was supposed to be different from the Neptunes, it must sound different, too. So the group abandon those tracks (they were later released as in the UK only) and recruited the band Spymob, from the Neptunes' own Star Trak Records, to articulate their new sound. The live instrumentation remains on Fly or Die – but Spymob do not. This time, it is Pharrell and Chad behind the instruments. "We've always played our own instruments in everything we do, but we convert them into programming for the final tracks," says Chad. "For Fly or Die, we decided to pick up the instruments and play ourselves and leave it like that. It's more honest and people don't know this side to us yet."

Lyrically, too, the group broke new perspectives. Pharrell goes deeper into exploring the side of his personality that most people don't get to see. "He's more quirky in real life than he is in videos and other people's songs," says Chad. Adds Shay, "He's a little more eccentric in his personality and in N.E.R.D he can pull that off."

The title track is one of the album's stand-out tracks, a heartfelt song about a teenager facing real issues and choices in his life. "Mommy, daddy, I know you love me / but if bad grades... Playstation … restriction, you take it from me / but God forbid that something goes wrong, you call the Police/ well, guess what I found in the drawer of daddy’s" Pharrell sings. "'Fly Or Die' is about choices," says Shay. "He's got an angel on one shoulder and the devil on the other and he's just trying to take the right path."

The subject in "Thrasher" isn't as conflicted. He's a person who deals with a bully on a daily basis and the confrontation and rage that lurk underneath the staid exterior. "We thought of 'Shook Ones' by Mobb Deep," says Shay. "Rock has never experienced that type of vibe. When I heard 'Shook Ones' in the club back in the '90s, I was scared for my life. I was literally shook. That's the feeling we tried to capture."

If many of the songs tap into the anxieties, awkwardness and aspirations of adolescence, it's no coincidence. "We didn't write these songs like that because we're obsessed with high school," says Chad. "But there are real memories from that time that shaped our lives and it just comes out naturally." Says Shay more succinctly, "I think those were some of the best years of our life, truth be told."

Which is where N.E.R.D lies – in the time-warp, where boundaries and borders and linearity succumb to the openness of truth. Because in life, there are two paths to choose from but only one direction to go in – and you can either Fly or Die.