A commendable little book on the Bohemian composer which like its subject seldom runs to extremes, except for the prefatory assertion that for Dvorak music was a raison d'etre ""to precisely the same extent"" as it was for Verdi. Mr. Hughes notes influences --Weber and early Wagner, Bohemian nationalism and folk sources, contemporaries--Smetana, Brahms, Wolf, keeps a running commentary on life and works. His analyses touch again on themes and influences, do not extend to notations. He follows Dvorak to Vienna, England, the U.S.A., where he headed the National Conservatory, keeping tabs both on career and avocations--pigeons and trains. Summing up, he sees Dvorak's weakness in his inability to decide what course to pursue, his derivative strains or ""pseudos""--but his strength, his versatility, contingent on this limitation. Not definitive but a quick study, orienting, introductory.