This article is an edited transcript of the Hilary Term Weinrebe Lecture, which was delivered remotely on 2 March 2021 at the Oxford Centre for Life-Writing, Wolfson College, Oxford. The lecture offers a personal and scholarly account of the reasons why the author decided to write a new biography of Sylvia Plath. It reviews Plath's popular and academic status as a feminist, confessional, 'mad' poet, and offers an alternative way of interpreting her life and work that rejects the pathological approaches of previous biographies. Also recounted are some of the challenges the author encountered over the course of eight years while researching and writing this 1,117-page biography.