Alberti, Guglielmo (1900–64). Italian writer, film director, critic. His book about Alessandro Manzoni, in whose honor the Verdi Requiem was composed, was published in 1973.

Alexanian, Diran (1881–1954). Armenian cellist, conductor, teacher, joint author with Pablo Casals of Traité théorique et pratique du violoncelle (Paris, 1922, English translation, Dover Publications, 2003). RK considered Alexanian to be one of the musicians who influenced him most and he credits his influence in the prefaces of several of his books, including Domenico Scarlatti and Interpreting Bach's Well-Tempered Clavier.

Balthus [Count Balthasar Klossowski de Rola] (1908–2001). French painter, illustrator, stage designer. He was well known for his portraits, and designed the sets for a production of Mozart's Cosi fan tutte at Aix-en- Provence in 1950.

Bartók, Béla (1881–1945). Hungarian composer, pianist, ethnomusicologist, known for the use of Magyar folk melodies in his compositions. His compositions included quartets, piano concertos, an opera, and orchestral works, including the popular Concerto for Orchestra, commissioned by Serge Koussevitzky and premiered in 1944.

Barzin, Léon (1900–99). American conductor of Belgian birth; teacher, violinist and violist; founder of the National Orchestral Association; founding musical director of the New York City Ballet.

Baudelaire, Charles (1821–67). French poet, essayist, art critic, translator of the works of Edgar Allan Poe.

Bauer, Harold (1873–1951). American pianist of English birth, known for his performances of Beethoven, Brahms, Schumann, as well as French composers such as Ravel and Debussy, associated with the Manhattan School of Music for many years. RK had hoped to study with him when he first went to Paris in the early 1930s (Bauer was in Paris at the time), but that didn't happen.

Beecham, Sir Thomas (1879–1961). English conductor and founder of a number of orchestras, including the London Philharmonic and the Royal Philharmonic. He was also associated with the Liverpool Philharmonic and the Hallé Orchestra and conducted opera at Covent Garden and the Metropolitan Opera.

Berenson, Bernard (1865–1959). American art historian and critic; leading authority on Italian Renaissance art. RK considered the clavichord recital he played at Berenson's Villa I Tatti in 1933 to be the beginning of his performing career.