Bela Bartok (1881-1945) was a very important 20th century Hungarian composer; Chalmers has written the most extensive biography available of Bartok.
The book is filled with insights into Bartok's life and music; e.g., "In March 1906 Emma Gruber introduced him to the man who was to become his firmest friend and ally, Zoltan Kodaly."
Concerning his religious beliefs, "He expresses a faith in nature and science, and sees atheism as the natural successor to Christianity ('distorted into Catholicism'), which in turn ('with its splendid code of ethics') had taken over from the faiths of the ancient world." Nonetheless, "Bartok was still nominally Catholic, but when his son reached school age in 1917 he joined the Unitarian Church, to exempt the boy from Catholic religious instruction at school."
Concerning Bartok's famous invention of the "arch" form (i.e., of the form ABCBA), Chalmers states that this "characteristic Bartok structure was actually a late decision on the part of the composer." He notes that "after the Fourth Quartet, (it) was becoming Bartok's regular choice of construction."
Bartok's famous Mikrokosmos pieces for beginning pianists were actually written because he was "dissatisfied with the music his son Peter was being given to play at his lessons."
Bartok wrote his famous Concerto for Orchestra (which was "symphony-like"), although he felt that "the symphony was dead."
This book is an excellent reference for anyone interested in Bartok or his music.