The Book of Sirach (/ˈsaɪræk/), also known as The Wisdom of Jesus the Son of Sirach, The Wisdom of Jesus son of Eleazar, or Ecclesiasticus (/ɪˌkliːziˈæstɪkəs/), is a Jewish literary work originally written in Biblical Hebrew. The longest extant wisdom book from antiquity, it consists of ethical teachings, written by Yeshua ben Eleazar ben Sira (Ben Sira), a Hellenistic Jewish scribe of the Second Temple period.
The text was written sometime between 196 and 175 BCE, and Ben Sira's grandson translated the text into Koine Greek and added a prologue sometime around 117 BCE. The prologue is generally considered to be the earliest witness to a tripartite canon of the books of the Hebrew Bible. The fact that the text and its prologue can be so precisely dated has profound implications for the development of the Hebrew Bible canon.