Agate made a short-lived, unsuccessful adaptation of a German play, "I Accuse!" from the original of Dr. Hans Rehfisch and Wilhelm Herzog; it opened and closed in London in October 1937. "The Times" reviewer commented, "Mr. Agate is suspected of having been too faithful to a too earnest German original." His theatrical notices appeared in a series of collections. including "Buzz, Buzz!", "Playgoing", "First Nights" and "More First Nights", and are valuable for their history of London theatre between the world wars. His anthology "The English Dramatic Critics, 1660–1932" is important. He wrote a biography of the French actress Rachel, a heroine, which Arnold Bennett called "excited and exciting" and of its subject "beyond question the best life in English".