Ezra

The book of Ezra starts off with the exact same passage that ends the book of 2 Chronicles.  This has led some people to think the books are written by the same individual.  Other people have suggested that the passage came initially from Ezra, but was then added to the end of Chronicles, or vice-versa.  Either way, it shows you how the events from Chronicles eventually lead up to the situation in Ezra, during the reign of Cyrus the Great.

Cyrus is a super fascinating person in history.  He ruled the Persian Empire at its height, taking over much of the "known world" of the time.  Interestingly, unlike most emperors with great power, Cyrus was actually a relatively benevolent ruler.  In fact, he was considered something of a rescuer to the Jewish people (many good things are said about him in Scripture, especially compared to other non-believing rulers [see Isaiah 45 as an example]).  The main thing that made Cyrus so different from other rulers is that he allowed the local people groups to practice their own religions, as well as have a certain amount of self-rule.  This was extremely important to the Jewish people.

The Book of Ezra is largely about how Cyrus enabled the Jews to return to their homeland and build a new temple after the Babylonians had destroyed the first one.  During the following decades as this went on, opposition developed and one of the following kings (Artaxerxes) was convinced by others to oppose the building of this temple.  However, the next king (Darius) was convinced to let the Jews return once more to re-building the temple.

The first half of the book describes the historical events surrounding this.  The second half re-tells these events from the perspective of Ezra, a priest who was dedicated to getting the temple re-built, as well as concerned about the intermarriage of Israelites with foreigners living in the area.  There was apparently a strong concern that the Israelites remain separate in their practices, which was not as easy now that they were no longer in total control of their land.  Marriage to foreigners seemed to be one of the main ways they were losing their separate ways and beliefs. Ezra leads the people to confess their sin, and the names of priestly families guilty of this are literally written down in the book for time immemorial.