On 1995’s Do You Want More?, the first widely available album by the Roots, there was a track called “Essaywhuman?!!??!” that was essentially an excuse for the group to jam, to show off that they were a rap band, with a guitarist, a bassist, a keyboardist and a drummer. At the time it was impressive as hell; now it sounds sort of quaint. But it also seems now like an important mark of what was to come, as in recent years the Roots have been ensuring that the band side of their music continues to evolve, that their brand of hip-hop continues to have a distinctly group-oriented musical sound.

Their landmark 2000 album Things Fall Apart was where The Roots began to really push themselves in unique musical directions while showcasing a strong hip-hop sensibility at the same time. The rhymes were sharp and the music was just as much so. Since then they’ve strengthened their sound immensely, using their abilities as a band in a seamless way, as evidenced through remarkable live performances, including an MTV Unplugged stint backing Jay-Z.

Phrenology builds from that base, with The Roots both filling their sound out and pushing it in a variety of directions. For the bulk of the album, The Roots play the form of tight soul/funk that it seemed like they had perfected on Things Fall Apart, but here it sounds even more exact, funkier and edgier. They’ve got their style down to near-perfection, and they’ve nicely augmented it with a batch of modern-day soul vocalists, including Musiq, Jill Scott, and promising newcomer Cody ChesnuTT.

What’s especially significant about Phrenology, though, is that the Roots have not just honed what their fans are used to but pushed themselves in new directions at the same time. This album will no doubt be a treat for all Roots fans near and far. The first pressing even comes with a DVD of rare videos and live performance footage that is like an unexpected Christmas gift for fans. But The Roots aren’t resting on their fan base. They’re moving right along, updating what they do.

In general, they’re letting rock sounds and attitudes seep into their sound, showing (like their compatriot Common does to an even further extent on his new album Electric Circus) that hip-hop musicians are aware of the grand legacy of black rock musicians like Jimi Hendrix, Funkadelic and Bad Brains. The most notable track on Phrenology where these influences come out is not the brief, somewhat inconsequential stab at hardcore called “!!!!!!”, but “Water”, a startlingly honest song about dealing with a friend who is losing himself to addiction. It’s a blatantly personal song, about a former member of The Roots, and has a sound that’s both intimate and rough. Halfway through “Water” the group go into space-rock mode, musically envisioning what a troubled mind might be like.

Phrenology is rock in attitude more than sound. “Rock You” kicks off the album as Black Thought’s statement that the group’s going to blow listeners away, and the rest of the album keeps that tone up. Even when they’re playing a love ballad or a more dance-oriented uptempo number, the Roots are out to impress you with what they can do.

The show-stopping approach is taken with the rhymes as much as the music. Black Thought comes off as both more rugged and even more precise than usual. His words and his phrasing simply knock you over, especially on a track like “Thought @ Work,” a mindblowing remake of Kool G Rap and Polo’s classic “Men at Work”, or the two blazing jams (“Rolling With Heat” and an unlisted bonus track) that pair Thought up with Talib Kweli, putting two of today’s best MCs side by side to show off their skills.

Though Phrenology slows down a bit near the end, with a track that tries hard to make a statement about society but feels fairly empty (“Pussy Galore”) and a love ballad that bears a sort of awkward-sounding chorus from Jill Scott (“Complexity”). but on the whole Phrenology is an impressive, ambitious work. The Roots have made the smart move of continually pushing themselves in new directions without taking any miscalculated jumps off of cliffs. Phenology is stunning, ranking right up there with the best hip-hop music of today.