Judy Montagu spent her late teenage years and early twenties directing anti-aircraft defenses during the Second World War as a Captain in Gunnery for the British Army. Demobilised in 1946, she set out in search of fun and freedom in America and found herself swept into a bright and glamorous social circle. She soon counted Joe Alsop and the Cushing Sisters among her new friends and even began to consider becoming a US citizen.

In 1949, determined to understand America more deeply, Judy embarked on a three-month tour of the country by Greyhound bus. Letters of introduction opened doors to a range of encounters, capturing an extraordinary moment at the height of the Anglo-American alliance. At each stop, Judy met newspaper editors, political leaders, and celebrities. In Texas - where she rode in a rodeo - she was the guest of Jesse H. Jones in Houston and Amon Carter in Fort Worth. In Hollywood, she had tea with Mary Pickford, and by the time she reached Illinois, her final state, she met and fell in love with Adlai Stevenson. As a cousin of Clementine Churchill, Judy's travels attracted regular press attention, adding another dimension to the diary.

The Greyhound Diary, edited by Judy's daughter Anna Mathias, is written in a snappy, well-paced style that reveals Judy Montagu's fascination with people and politics. She is generally generous in her portraits of fellow travellers, while offering a more caustic, often witty, take on her grander hosts.