Agatha Mary Clarissa Miller was born on 15 September 1890 in Torquay, England.  Her father, Frederick, was an outgoing American with an independent income.  Her mother, Clara, was rather shy; Agatha resembled her greatly in personality.  There were two other children - Madge and Monty, both older than Agatha.

Although Madge received a formal education, Clara decided Agatha should not.  She wanted Agatha to be taught to read when she was eight; however, by the age of five Agatha had already taught herself to read.  The rest of her education was through a mixture of tutors, part-time schooling and French finishing schools. She also trained as a singer and pianist and if it had not been for her extreme shyness, she would have had the talent to have made this her professional career.When Agatha was eleven her father died and she became even closer to her mother. Without Frederick, Clara became restless and began to travel, at times taking Agatha with her; these early trips began Agatha's lifelong love of travel.

In 1912 Agatha met Archie Christie, her future husband, a qualified aviator who had applied to join the Royal Flying Corps.  After a tempestuous romance, they married on Christmas Eve 1914, by special licence, with Archie returning to the war in France on Boxing Day.

Agatha was not lazy during the war. She became a nurse in the Voluntary Aid Detachment of the Red Cross Hospital in Torquay - ultimately working in the dispensary where she enjoyed the work and completed the examination of the Society of Apothecaries.

Agatha’s happiness was complete when Rosalind, her only daughter was born on 5th August 1919 but by 1926, her life was in tatters: Christie’s mother Clara died and Archie left her for another woman.

Christie slowly rebuilt her life and in 1930 she visited Baghdad for a second time. It was here where she met Max Mallowan. Max took Agatha on a tour of Baghdad and the desert - it was an action-packed journey - their car got stuck in the sand and they were rescued by the Desert Camel Corps! When they reached Athens, Agatha received a telegram saying that Rosalind was seriously ill. Agatha's only concern was to get home, but she had badly sprained her ankle on an Athens street and was unable to walk. Max chose to accompany her back to England. She could not have made the trip without him and when they reached home he proposed and she happily accepted.

Agatha accompanied Max on his annual archaeological expeditions for nearly the next 30 years. She continued to write, both at home and on field trips and her book Come, Tell Me How You Live wittily describes her days on digs in Syria.  She and Max were happily married for 46 years.  After a hugely successful career and a wonderful life Agatha died peacefully on 12 January 1976.

      Adapted from

http://agathachristie.com/about-christie/christies-life/biography/

You can read Agatha Christie's own account of her life in An Autobiography which was published after her death in 1977.