Known for the exuberant imagery of films such as Carriage Trade and especially for their intricate and innovative editing, he has been described as "the supreme Romantic diarist of the cinema"[1] as well as "both a probing and playful artist and a keen intellect reveling in the interplay between all the creative arts.

"[2] "Critics have tried to pin down Sonbert's cinema with catchy formulations," wrote David Sterritt, but "his works are not really diary films, since their carefully shaped contours are determined more by aesthetic insight than daily experience, and to compare them with 'explosions in a postcard factory' is to acknowledge their boisterous variety while missing their ecstatic precision.

"[3] A protégé of the avant-garde filmmaker Gregory J. Markopoulos but inspired by the work of Hollywood auteurs like Alfred Hitchcock and Douglas Sirk as well as by experimental cinema, Sonbert premiered his first, short films, to critical enthusiasm, in 1966 while a student at New York University.

The films that followed captured his friends at work and play, often in studios, galleries, or boutiques, and were frequently accompanied by rock songs of the recent period, whose energy added to the power of their rapid editing.

"[4] Roger Greenspun's review of a 1968 retrospective in New York began: "During the last weekend in January the Film Makers' Cinematheque offered a three-and-one-half-hour program consisting of the collected, but not quite complete, works of Warren Sonbert.

"[8] Intercutting footage shot with his 16mm Bolex during "travels over four continents in six years," Carriage Trade was the first in a two-decade succession of films with similarly radical montage, in which each cut was designed to open up multiple connections and associations.

"From the first stunning cut, between building reflections in twin panes of glass and a distant waterfall that divides the frame similarly, the editing both expands the film's space and creates a variety of links between shots," wrote Fred Camper.

"[11] While Carriage Trade is still sometimes considered his masterpiece (Sonbert himself once called it "my magnum opus"[12]), the critic Paul Arthur has argued that "with every successive film the overall shape and rhythmical patterning shift in relation to a particular exploration of theme or set of motifs.

In his editing, the images took on a new life; uncoupled from literal meanings and quotidian contexts, they became notes or colors ... Like the Russian montage master Dziga Vertov, Sonbert saw film as a language, and his work demands to be read ...