The name of the book comes from one of its main themes: the departure of the sons of Israel from Egypt. There is much more to the book than this, however. There is the introduction of the zenith of prophets in OT tradition, Moses, as well as specifics surrounding Torah (chs. 20-23) and the tabernacle (chs. 25-40).
Various theories abound regarding the book’s historicity, especially with the presence of Israel in Egypt. These theories range from the pharaoh of the Exodus being Ramses II (1279-1213 BCE), to the whole book being written at a very late date and having no historical reality whatsoever. Various clues within the book show the reader that either theory is workable, which is problematic for those in the field of Biblical Studies. In the end, the writers of the book probably did not have the same ideas of accurate historicity that modern minds have, and the book is probably a mixture of myth and reality. It is best read as a story in its final form, demonstrating that God is one who intervenes in real history (and not a deity who acted only in primeeval times) for his people.
The book has been the catalyst for much of Israel’s tradition. Indeed, several festivals look back to the Exodus tradition in reverence: passover, unleavened bread, festival of booths, festival of weeks, etc. The main idea of the book throughout tradition, if one wishes to make reductionistic conclusions surrounding its content, probably boils down to Exodus 20:3 (1-6). The contention between worshiping Yahweh alone and incorporating him syncretistically into other pantheons continues throughout the remainder of the Pentateuch and well into the Historical Books (Joshua through Kings). Another key verse in the book is Exodus 7:16, which reads:
The LORD, the God of the Hebrews, sent me to you to say, “Let my people go, so that they may worship me in the wilderness.”
The verse shows implicit causation — pharaoh is to let the Hebrews go so that they may cease to serve him and start to serve Yahweh. The people, then, exchange one master (pharaoh) for another (Yahweh). The book is primarily a story of oppression and redemption through the power of God.
The book begins rather abruptly, insomuch that if one blinks enough, the childhood of Moses might be missed. The author clearly wants to introduce Moses, but at the same time wants to move the story along quickly in order to get to the main setting in Egypt and then in the wilderness. The book ends climactically with the blessing of the presence of Yahweh’s glory (kabod) at the tabernacle. This motif is repeated when the temple of Solomon is dedicated in 1 Kings 8. The presence of Yahweh (or rather, the presence of “his name”) is the paramount blessing in the narrative.
For Mormon studies, the book became the allegorical focal point of our own exile from the midwestern United States to the desert of the Salt Lake Valley, especially as manifested in hymns such as “Redeemer of Israel.” Also noteworthy is the emphasis on the divine cult, the giving of the law to the people, and the reward of the presence of God in his own “dwelling place” (Heb. mishkan), all characteristic goals of Mormon ritual and worship. Likewise, discussion of the anointing of Aaron and the priests before entering the tabernacle (40:12-15) has mention our rituals.