[7] During the war, Cooper wrote daily to her husband, giving him regular updates on their two children, including their son's stages of development from infant to toddler and little boy.

[14] In early 1934, when his mother left England to expand her stage career into North America, Buckmaster moved to a flat in Chelsea with his nanny, Sarah Aves, to keep home for him.

[17] They lived mainly in California and worked extensively in both Hollywood and Broadway, also supporting the Red Cross British Relief Fund and running a small theatre for servicemen during World War II.

[18] John Buckmaster was very fond of his stepfather Merivale, upon whose death, on 12 March 1946, he wrote a tribute poem and left it on his mother's desk one morning.

[26] As a handsome and talented young actor, he had inherited her gift for mimicry that later put him in the top flight of cabaret artists on Broadway,[27] and seemed poised to follow her success on the stage.

[29] In the title role of this play, Robert Morley—who became Buckmaster's brother-in-law after marrying his sister Joan on 23 February 1940[30]—had made something of a sensation, repeating on Broadway the performance he had given at the little Gate Theatre in London a year earlier.

Nowhere in the world is success in the theatre so enjoyable as in that city, where all the head waiters know your weekly box-office takings, and all the cab drivers are out front on your opening night.

[36] By the Spring of 1943, Buckmaster had enlisted as a private in the United States Army Air Forces, and composed a song he contributed to one of the Service magazines shortly after he joined.

[48] From the beginning of his stage career, Buckmaster featured regularly in gossip columns as the escort of up-and-coming young actresses such as Vivien Leigh and Jean Gillie.

[50] At Vivien Leigh's insistence, Buckmaster—who seemed to know everyone in the theatre[51]—introduced her to Laurence Olivier in the autumn of 1935 at the Savoy Grill, where he and his first wife Jill Esmond dined regularly after his performance in Romeo and Juliet.

[54] In the summer of 1945, when they were both on leave at the family home in California, Jack Merivale noticed uneasiness in Buckmaster's relationship with his mother: "Whenever I'm with her, I feel I'm always doing the wrong thing, whatever it is.

"[39] At the end of the Lady Windermere's Fan run in the spring of 1947, Buckmaster suffered the first of the regular mental breakdowns which became increasingly violent over the following decade, even though shock treatment was at first successful in containing his acute schizophrenia.

[41] In his 1979 biography of Gladys Cooper, her grandson Sheridan Morley summarised the presumed causes of Buckmaster's condition: [T]he strains of a war in which he'd felt himself perhaps involved too distantly and too late, of a number of increasingly unhappy love affairs, and of maintaining a career which had begun with rather too much glitter and not enough training, were proving too much for John, and under those pressures and the other pressure of being Gladys's son he was now, slowly but surely, to crack – temporarily at first, then for longer periods until in the late 1950s a series of increasingly effective drugs were able to bring him to his present and very controlled state.

In February 1952, Buckmaster, having just finished a highly successful and critically acclaimed Broadway run as the Dauphin in St Joan, had the worst and most violent of his mental breakdowns.