Memoirs of the Twentieth Century

Memoirs of the Twentieth Century is an early work of speculative fiction by Irish writer Samuel Madden. This 1733 epistolary novel takes the form of a series of diplomatic letters written in 1997 and 1998. The work is a satire, perhaps modeled after Jonathan Swift's Gulliver's Travels (1726). Madden was an Anglican clergyman, and the book is focused on the dangers of Catholicism and Jesuits, depicting a future where they dominate.

The book was published anonymously. Soon after it was published, Madden seems to have had most copies destroyed. Although this would mean the book had little influence in its own time (with a negligible contemporary readership and no real impact on later writers), the book is notable as an early work to feature time travel. In his 1987 work Origins of Futuristic Fiction, Paul Alkon describes the book as the earliest in English literature to feature time travel, but notes that it does not explain how it was performed. In the 2008 book Physics of the Impossible, Michio Kaku calls the work arguably the first account of time travel in fiction.