Book excerpt: Early in his career, Bach began to transcribe for the keyboard a number of concertos for violin, oboe, and other instruments by such baroque masters as Vivaldi and Telemann. His purpose: to study and explore the works of other composers as well as to supply good clavier music for his own performances. This collection of sixteen of these celebrated transcriptions is reprinted from the definitive Bach-Gesellschaft edition prepared by Ernst Naumann and presented in a study format designed to give amateur and professional pianists and harpsichordists a lifetime of pleasurable study and use. Six of these glorious keyboard works are known to be transcriptions of Vivaldi violin concertos. Three are based on concertos written by Duke Johann Ernst of Saxe-Weimar, the son of Bach's employer at Weimar. One is based on a violin concerto by Telemann, another on an oboe concerto by Alessandro Marcello, and another on a concerto by Benedetto Marcello. The sources of the remaining works are unknown. Vivaldi, whose music Bach probably first heard in 1712, was to provide a strong influence on the young composer. Bach would eventually assimilate the Italian's style and use it with his own contrapuntal heritage and the Northern idiom in creating what we recognize today as the typical Bach style. These transcriptions, which represent his introduction to the new idiom, richly display a dynamic virtuosity that makes their performance an exhilarating experience.