De Ira or “On Anger” is an essay on anger by Seneca the Younger. The work offers advice on controlling anger and to make it subject to reason. This essay contains an active table of contents for easy maneuverability throughout the eBook.
It is not clear to scholars who wrote the first work on the subject of passions or emotions (the terms are thought interchangeable), but while Xenocrates (396/5–314/3 BCE) and Aristotle (384–322 BCE) were students at Plato's Academy, a discussion on emotions took place which provided likely the impetus for all later work on the subject. The Stoic Posidonius of Apamea (c.135 - 51 BCE) is considered the main source for Seneca, also the work of Theophrastus, Antipater of Tarsus, Philodemus of Gadara, Sotion of Alexandria, Xenocrates (active sometime after 346 BCE) and Aristotle (c. 384-322 BCE ). Other influences may have included works On Passions by the Stoic philosophers Zeno of Citium, Chrysippus, Aristo of Chios, Herillus, Hecato of Rhodes, and the Peripatetic philosopher Andronicus of Rhodes (c. 1st century B.C.).
Within the context of Stoicism, which seeks to aid and guide the person in a development out of a life of slavery to behaviors and ways of the vices, to freedom within a life characterized by virtue, de Ira posits this as achievable by the development of an understanding of how to control the passions, anger being classified as a passion, and to make these subject to reason.
Seneca's thoughts of the relationship of the passions to reason, are that the passions arise in a rational mind as a result of a misperceiving or misunderstanding of reality.