For several decades, original cast recordings of Broadway musicals regularly inhabited the lofty upper reaches of popular music sales charts. Even now, many people (especially those who live outside of New York), depend upon these albums to get a taste of what current audiences are cheering about. D.A. Pennebaker's entertaining and irreplaceable documentary on the making of the '70s cast album of landmark musical Company offers a fascinating glimpse behind the scenes at a typical recording session. The vast majority of the film consists of candid moments and performances, rather than direct interviews. Shots of composer Stephen Sondheim shaking his head over a mistake of which only he is aware or insistently coaching Pamela Myers on the correct pronunciation of "bubbi" reveal his commitment to making the album perfect. Producer Thomas Z. Shepherd's own perfectionist tendencies are also well captured, as is the willingness of the cast to perform take after take, although that willingness inevitably wanes as nerves fray from the long hours. Elaine Stritch's anger and frustration as she tries, after 18 grueling hours, to tackle the show-stopping but daunting "The Ladies Who Lunch" is palpable, as is her sense of defeat when it is decided that she will come in the next day for a final take -- which comes out brilliantly. Obviously filmed on a budget, production values leave much to be desired, but the power of the performances and the claustrophobic yet exciting atmosphere caught by the film more than make up for that. Originally intended as the first in a series of documentaries about original cast albums, no others were ever made, making Company that much more valuable.