A fairly massive, 4-disc set documenting seven performances by shifting personnel over the period from 1967 to 2007. Even considering the almost five hours worth of music contained herein, it's impossible to say how representative a sampling this is. What's presented, however, runs the gamut from excellent to, frankly, pretty bad.

Alvin Curran, Frederic Rzewski and Richard Teitelbaum are the constants here, appearing in each performance, though their playing companions vary quite a bit. Garrett List and Steve Lacy put in the most time otherwise, their presence imparting both some of the finer and the more problematic moments. The earliest set, SpaceCraft from 1967, shows MEV at possibly its most anarchic, a swirling noisefest that bears at least a small comparison with AMM's "The Crypt" from the following year. MEV is often paired with AMM in historical recaps of the era, but there is really not very much common ground, the former being a far looser group as far as an explicit philosophy goes, incorporating more of a jamming aesthetic and never eschewing either jazz-based improvisation or thematic materials, even "solos". But at this point they could still generate a goodly amount of heat, joined here by original members Allan Bryant, Carol Plantamura and Ivan Vandor. Oddly, one gets the sense that there is far more imaginative freedom at play in 1967 than in much of the later material.

The standout piece, however, is 1972's "Stop the War", recorded at the studios of WBAI in New York. Joined by List (trombone), Gregory Reeve (percussion) and Karl Berger (marimbaphone), MEV fashions a dense, buzzing jungle of sound, extremely rich and evocative. Berger's mallets go a long way toward assisting here, blending very well with Curran's thumb piano and Reeve's earthy drums; a pity he didn't record with them more often. Unlike in later performances represented here, Rzewski's piano is very much to the point, beautifully balanced between abstraction and the blues and folk-oriented forms he was beginning to investigate around this time, as well as incorporating references to minimalism. It's a stunning set, cohesive, even throbbing with life. Whether it's worth the price of the entire package is another question because the road gets rocky from this point.

One is tempted to speculate that the three principals lost something of their zest for pure improvisatory interaction, having evolved into other concerns of a somewhat more compositional nature (or, in Teitelbaum's case, of investigation into interactive software systems). The 1982 performance at the Stedelijk Museum, with Lacy and List on hand, is leagues away from the one a decade prior, in most respects a kind of humdrum improv set. Rzewski's free playing has become much more stilted than previously; instead of delving into that lovely, obliquely tonal area he'd found earlier, he vacillates between dry, academic sparseness and Taylor-ish pyrotechnics. Here, as in much of the remainder of the recordings, some of the synth work (I'm guessing more at the hands of Curran than Teitelbaum) sounds horribly dated and cheesy. Lacy blithely solos over the noodling, seemingly paying little heed to what's occurring around him. To be sure, the group meanders into sections where things suddenly gel and there are several beautiful minutes, small crystal islands in a sludgy river, but it's a lot to ask for those passages to assume so much weight. The second section from the same museum concert revolves around a Lacy composition whose theme is typically lovely and linear. Ironically, when the ensemble adheres most closely to the motif, the result is quite gratifying but when they arc into freer playing, things dissolve rather quickly. A Knitting Factory set from 1989 (at which this writer was present) with the same personnel and one from Bern in 1990 with only List (someone here — Curran? — is guilty of some seriously painful vocals) are similarly inconsistent: desultory playing for the most part, livened here and there by small eddies of sensitivity or sudden congealings of intent but marred by an overall formlessness and an insistence on what is often perceived as call and response playing rather than real group interactivity.

The fourth disc contains a lengthy performance from 2002 in Italy, where trombonist George Lewis joins the quintet from the prior date. It's a generally more pensive, considered set, percolating well when the cast keeps things on a low simmer, less so when Rzewski improvises wildly (again sounding like any dozen post-Taylor pianists) or when written passages intrude. But the restraint shown overall (despite another wretched vocal interlude, this time from List crooning "You Are My Sunshine") and the lovely sound of the twinned trombones goes a long way toward making this the strongest set since the one at WBAI of those represented herein. The final track is something of anomaly but a relatively pleasant one, an 11-minute cut featuring only the core trio in concert at Tanglewood in 2007. The samples, as is ever the case it seems, are too obvious and clichéd (here, right-wing talk radio, among others), but the nest of sound created, apparently largely Teitelbaum's doing, is rich, subdued and complex. When Rzewski interpolates "Taps" into the mix, it actually works less awkwardly than one would suspect, if only due to the listener's understanding of the context of the time.

For MEV fans, a no-brainer, for others, it's least an intriguing historical document. Those on the AMM side of this particular divide will doubtless be put off by many of the antics while listeners coming at it from a more jazz-oriented free improv direction, especially if they've not experience MEV before, might well become enamored.