The composer Lehman Engel (1910-1982), a legendary critic of the musical theatre, was arguably the first one to develop a theory on the structure of the stage musical. In his book on the subject, "Words With Music", he wonders why some American musicals are more successful abroad than others. He comes to the conclusion that all depends on the quality of what he calls "the transformation" of the original material. It must be based on a profound understanding of the mentality of the country where the musical is exported to. "This transformation process is a far more complex one than the word translation would indicate, because the adaptor has the problem of preserving the spirit of the original while making no effort to achieve a word-for-word rendering. In my opinion, the successful outcome of a transformation can only be accomplished when the original material is indeed universal and the adaptor is sufficiently creative to see it through the eyes of the local audience."