This book is all about Israel and the coming of the Lord Jesus Christ.
Jesus prophesied the death of the nation of Israel when He cursed the fig tree and it withered up and died. Forty years later, Israel was overrun by Titus and the Roman army, and the inhabitants were scattered to every nation.
Through the prophet Jeremiah, God promised to regather Israel back to that land, which was literally fulfilled in 1948. But Israel came back exactly as they left -- spiritually dead.
In a vision, God showed the prophet Ezekiel the mountain of dry bones and declared these bones to be the house of Israel, which means they were dead to God. God asked Ezekiel, "Can these bones live?" This book answers that question and shows the nearness of the coming of the Lord.