Lillian May Forrester was born in 1880 to Samantha Rixon and John MacFarlane Forrester in Melrose, a tiny farming community in Tyendinaga Township, Hastings County, Ontario, near Belleville. The family moved to southern Manitoba in 1881, settling on a farm in the Aux Marais district, near the town of Emerson and the U.S. border. She served for a while as a school teacher, and in 1905 graduated from the Winnipeg General Hospital School of Nursing (now the School of Nursing of the University of Manitoba). She was an active member of King Memorial United Church for many years and was a life member and past president of the Women's Missionary Society. Mrs. Hamilton was also a past president of the Medical Faculty Women's Club, University of Manitoba, and was a member of the Women's Musical Club.
In 1906, she married Dr. Thomas Glendenning (T.G.) Hamilton in Elmwood. In 1909, their daughter Margaret Lillian was born; in 1911, their son Glen Forrester; and in 1915, their twin sons Arthur Lamont and James Drummond. The loss of Arthur in 1919 to the influenza epidemic encouraged the Hamiltons to engage with questions of life after death, and eventually establish the well-known Hamilton experiments in psychic phenomena, including the holding and recording of séances at their home, and other psychical research. Starting in the 1920s, Lillian not only helped organize and participated in the séances, but also carried out a large part of the secretarial work of researching, filing and analyzing the records; she also helped to prepare many of Dr. Hamilton's papers and articles. After T.G. Hamilton’s death in 1935, she carried on the séances and psychical research. From 1939-1940, she conducted two series of experiments with Hugh Reed, including several previous members of the Hamilton group, notably the medium Mary Marshall (aka “Dawn”). Lillian Hamilton brought the Hamilton investigations to a close in 1944, by which time the group had largely dispersed.
With her youngest son James D. Hamilton, Lillian completed the manuscript about the T.G. Hamilton research which was published as Intention and Survival in 1942. Until Lillian's health began to fail in 1955, she continued study of psychic matters and undertook the indexing and care of the Hamilton records. In the early 1950s, she and her daughter Margaret Hamilton Bach began collaborating on the work that was eventually published by Margaret as Is Survival A Fact? in 1969. Lillian died on 18 September 1956 in Concordia Hospital in Winnipeg.

Dr. T.G. (Thomas Glendenning) Hamilton was born in Agincourt, Ontario in 1873. In 1883, his family moved west to Saskatchewan and was among the first pioneer families to settle in Saskatoon. After his father died in 1891, his mother moved the family to Winnipeg where young T.G. Hamilton attended Manitoba College. He graduated from medical school in 1903, completed his internship at the Winnipeg General Hospital in 1904, and commenced practice in the district of Elmwood within Winnipeg in 1905. In 1915, he was President of the Manitoba Medical Association. Hamilton also served on the Public School Board for nine years, one year as chairman. He was also elected a member of the provincial legislature in 1914-1915. In 1918, Hamilton investigated paranormal activity briefly, but began in earnest in 1920 after the death of his three year old twin son Arthur. His aim was the investigation of paranormal phenomena such as rappings, psychokinesis, ectoplasms, and materializations under scientific conditions that would minimize any possibility of error. His work became known in the United Kingdom, Europe, and the United States. Between 1926 and 1935, he presented eighty-six lectures and wrote numerous articles that were published in Canada and abroad. Dr. Hamilton's wife, Lillian, carried on his paranormal experimentations following his death in 1935.