The sub-series consists of the correspondence of Mona Barclay Hogg (and a few letters to her husband Robert Hume) which is divided into nominal files and chronological files. The letters from her friends and family reveal much about her life as a young woman and then middle-class mother and widow in English Canada in the first half of the 20th century. Letters from her sons also tell of their experiences as children attending Trinity College School in Port Hope. Some of her correspondents are of special note, however, including Rev. Charles W. Gordon, better known as the author Ralph Connor, who had been a close friend of her father's (2 letters and a telegram) and Mary Conan Doyle, daughter of the celebrated author, whom Mona had met in 1907 in Dresden, Germany while studying music (10 letters). Her son John J. Hume was her most frequent correspondent but other regulars included Josephine (Hogg) Campbell, Dorothy (Webster) Church, Richard Craig, Mary (Hume) Galt, Francis Higginbotham, Arthur Hogg, David Hume, Robert Hume, Dorothy Kirkwood, Mary (Higginbotham) Lockard, Brian O'Grady, Grace Webster, and Siri Webster.
Her correspondence is a surprisingly valuable source for the two world wars. She received twenty letters from her brother Arthur Hogg describing his First World War service with the Scottish Horse Regiment and the Royal Flying Corps, and she kept another eleven letters from him to her sisters. Arthur Hogg describes his work in a hospital operating room in 1915 and his transfer to the Royal Flying Corps in September 1916, including his first solo flight and an attack on German aircraft. He was wounded in action in June 1917. During the Second World War, her son David Hume wrote her 33 letters while on active service from 1943 to 1945 with the Royal Canadian Air Force. They portray his training as a bomb aimer at No. 1 Initial Training School, Toronto; No. 1 Bombing and Gunnery School, Jarvis, Ontario; and No. 9 Air Observer School, St. Jean, Quebec, before going overseas in the last weeks of the European war. There are also about 20 letters from Davis Braly, 1940-1943, an American friend who served in the Victoria Rifles with John Hume and later joined the RCAF.
The correspondence from her son John J. Hume is the most voluminous in the sub-series, comprising over 300 letters that primarily document his service in the Canadian Army during the Second World War. His letters home from St. John's, Gander, Victoria, and Nanaimo give a strong flavour of the tedium of home defence duty and the soldiers' frustration at being on the margins of the war. His time in England, however, produced a deep affection for the English people which is reflected in his writing although at times he was not uncritical of English society. Face-to-face with British sentiment, his Canadian nationalism flourished and led him to identify differences between the two peoples, including, in his view, the greater racial tolerance of Canadian society. Mona Hume's pro-British sentiment frequently provoked her son to dismiss the idealism of those at home and his private school upbringing. In other letters from England, he described London in the blackout, going to the circus and shows, the Beaver Club, travels in the countryside, visiting friends and relations, and the daily routine, trials, training, and drills of camp life at Aldershot. His letters from North Africa, Sicily, and Italy, tell of the local colour and contrasts and the people he met. Hume also chided his mother for her uncritical acceptance of CBC radio news about the war in Italy. The letters home are numbered so the few missing letters can be identified and the others cross-referenced with his mother's letters to him in the John J. Hume series. In conjunction, the two sets offer both sides of a close mother-son relationship in wartime.