The life of Mary, Queen of Scots, is examined from her infancy to her execution, exploring the political and personal decisions that led to her downfall. John Guy's biography meticulously reconstructs the tumultuous life of Mary, Queen of Scots, utilizing a vast array of documentary evidence. The narrative traces her journey from her coronation as an infant to her execution in 1587, delving into the controversial decisions she made, such as her marriage to Lord Darnley's murderer, Bothwell. It further details the desperate circumstances of her imprisonment by Elizabeth I and her eventual entrapment by Elizabeth's spymaster, Sir Francis Walsingham, which sealed her fate.

This biography is regarded as a thorough and well-researched account of Mary, Queen of Scots' life. The author's reliance on extensive documentary sources provides a detailed and nuanced perspective on her reign and personal choices. It is noted for its exploration of the complex political landscape of 16th-century Britain and the intricate relationships that defined Mary's fate. The work offers a detailed look at the events leading to her execution, making it a significant contribution to historical scholarship on the period.