J. Fillion-Lahille has argued that the first book of the De Ira was inspired by the Stoic philosopher Chrysippus' (3rd-century BC) treatise On Passions (Peri Pathôn), whereas the second and third drew mainly from a later Stoic philosopher, Posidonius (1st-century BC), who had also written a treatise On Passions and differed from Chrysippus in giving a bigger role to irrational aspects of the soul.

[2] In consequence, although Seneca may have used both treatises by Chrysippus and Posidonius, his main inspiration is now thought to be chrysippean.

[6] Book III begins with its own introduction on the horrors of anger,[8] and can be read on its own, which has led to suggestions that it was devised either as a later appendix to the work, or that it was a separate treatise in its own right.

[9] Ira is defined as anger, wrath, rage, ire, passion, indignation – primarily, to be angry.

The work's first sentence reads:[6] You have asked me Novatus to write on how anger can be mitigatedAlthough split into three books, De Ira is effectively divided into two parts.

The second part (Book II.18 onwards) begins with advice on how the avoidance of bad temper can be taught to both children and adults.

This is followed by numerous snippets of advice on how anger can be forestalled or extinguished, and many anecdotes are given of examples to be imitated or avoided.