Ezra
Ezra, had a royal commission that authorized him to "inquire concerning Judah and Jerusalem, according to the law of thy God" (v. 14). As a result, he and Nehemiah focused Israel's new identity on the LORD GOD's law brought forward from Moses. Israel was forced to focus on the form and content of religious life and practice, as the Babylon exiles returned as faithful Israelites, and reestablished their temple worship.
There were three groups of returns from Babylon to Judah. The first led to the rebuilding of the Temple of the LORD, the second was under Ezra, and was focused on reformation and returning to their covenant obligations, and the third was led by Nehemiah. The identity of the author of this book cannot be established with certainty, however, Jewish tradition names Ezra as the original author, with Nehemiah completing his work. Most modern scholars agree with this attribute to Ezra, "the chronicler".