A righteous undertaking of great magnitude, What It Is! Funky Soul and Rare Grooves trawls through a decade-long stretch of the Warner-distributed archive -- taking in the catalogs of Warner Bros., Atlantic, Reprise, Atco, and smaller nodes like Cotillion, Curtom, Alston, and Jonie -- and pulls up 80 soul/funk truffles, almost all of which were left for dead shortly after release. While many of these cuts have been repurposed as vital ingredients of hip-hop tracks, which has in turn fostered a voracious collector's market (it would cost a fortune to collect these songs in their original formats of release), the box is a leagues-deep trawl through an otherwise forgotten past. There are few well-known names on these four discs, but even they tend to be represented by selections that are not obvious. Curtis Mayfield's "(Don't Worry) If There's a Hell Below We're All Going to Go" is likely the best-known inclusion, and after a substantial number of cuts that can't be considered truly rare, there's a sudden drop into (sweet, sweet) oblivion -- unless you're of the small minority whose spines tingle at the sight of names like Grassella Oliphant and Rasputin's Stash. The chicken-scratch guitars, wild Hammond B-3 runs, group chants, and blaring horn punches are served by the dozens, but the box also illustrates an evolution that took place through the '70s. Since the sequencing is, for the most part, chronological, those changes are all the more perceptible. Funk Factory's "Rien Ne Va Plus" and Faze-O's "Riding High" churn and float slowly, steeped in synthesizers, electric pianos, and studio effects, while legions of artists have attempted to replicate the sound and spirit of Stanga's "Little Sister" and 6ix's "I'm Just Like You" -- two songs graced by the hands of Sly Stone in tripped-out, otherworldly There's a Riot Goin' On mode. It's not one big party, either. Check Baby Huey & the Baby Sitters' harrowing "Hard Times" (written and produced by Mayfield), where the poor and paranoid protagonist subsists on Spam and Oreos and keeps his curtains drawn so he won't see those who peer in on him. The themed playlists and imaginary compilations hiding within this compact box are innumerable, bound to take the average overthinking funk freak to new levels of nerd-dom. There are region-specific sets to be made, as well as sets with possible titles like Latin Funk and Flute Funk and The Early Arrangement and Production Work of the Late Arif Mardin, in addition to a remarkable batch of covers, a tight collection of instrumentals, and a not-very-exclusive list of tracks that have been sampled throughout the years. The accompanying booklet could be sold separately, as it contains scads of seldom-seen photos and scholarly track-by-track notes. Rhino also deserves applause for resisting the urge to house these discs in a massive synthetic afro or an oversized wah-wah pedal. You can snugly tuck this thing between your arm and chest and sense its power run through your whole body. Bring on a second set that extends past the disco era and involves the likes of Slave, Mass Production, Brides of Funkenstein, and Dinosaur.