A compilation of leftovers from Ornette Coleman's tenure on Atlantic (1959-1961), "Twins" is a piece whose value has diminished. This was far and away the most productive time of Coleman's career, he recorded six albums worth of material, including at least two classics ("The Shape of Jazz to Come", "Free Jazz"), and there was enough leftover material to produce three albums of reasonable quality and include half a dozen extra tracks on top of that in a boxed set. Given that this represents about a third of his recorded output over his nearly fifty year recording career, there's something to be said for this material.
The album received its name from the inclusion of the rehearsal take of "Free Jazz", cleverly titled "First Take". Featuring two quartets playing together-- one of Coleman's then working band of himself on alto, Don Cherry on trumpet, Charlie Haden on bass and Ed Blackwell on drums and a second quartet of Eric Dolphy on bass clarinet, Freddie Hubbard on trumpet, soon-to-be Coleman bassist Scott LaFaro and former Coleman drummer Billy Higgins. The piece has the same general setup as "Free Jazz", but everything is cut in half in terms of solo space-- the interactions, structures, etc. are all still there. But this really isn't all that valuable since it's included as a bonus track to the "Free Jazz" release.
As such, the value of the record now lies in the other four tracks, leftovers from sessions during his Atlantic tenure. The problem is they FEEL like leftovers-- Cherry runs out of steam on his solo on "Little Symphony", "Check Up" is lifeless barring LaFaro's unnervingly brilliant playing, and "Joy of a Toy", while nicely performed, isn't among the better of Coleman's material. The exception to all of this is "Monk and the Nun", leftover from the first session on Atlantic-- Coleman and Cherry both take superb solos after the chirping theme is stated.
Granted, none of it is unlistenable, it's just not that excited, and with a large portion of it duplicated elsewhere, it's totally unnecessary. If you're into Coleman enough to check out this obscure record, I'd advise looking into the boxed set "Beauty is a Rare Thing", which collects all the material from these sessions.