Parfit rose to prominence in 1971 with the publication of his first paper, "Personal Identity". His first book, _[Reasons and Persons](https://en.wikipedia.org/wiki/Reasons_and_Persons "Reasons and Persons")_ (1984), has been described as the most significant work of moral philosophy since the 1800s. His second book, _[On What Matters](https://en.wikipedia.org/wiki/On_What_Matters "On What Matters")_ (2011), was widely circulated and discussed for many years before its publication. `Concepts:` [[Philosophy]] `Knowledge Base:` [[Morality]]