There is nothing in the New Testament that is like this book. In many ways, it is like a letter. However, it does not have the typical greeting that most New Testament letters have. The author wrote powerfully about why Jesus, who is the Messiah, is the Lord and ruler of all things. The author also wrote about how followers of Jesus need to think and behave in ways that honor God. They need to do this all the time because they are Christians.
The author wrote to people who were Jewish Christians. They were discouraged because other people were persecuting them. They were tempted to return to their former beliefs and following the Law of Moses.
The author wrote strongly that Jesus is greater than everyone and everything. He did this by comparing Jesus to angels, prophets, and priests. He showed that Jesus is greater than all of them. This is why God made Jesus ruler over all things, especially the better world that God will create in the future.
The author wrote that Jesus changed everything and people should not try to obey the Law of Moses. Jesus taught a new way of thinking and living. Jesus gave Christians a special confidence for how the future will be. So, Christians need to think the way Jesus taught them to think. They need to live in a way that they know God will create this special future world for them.
Scholars think the author seemed to know the people to whom he wrote. He was comfortable in challenging them and warning them to live in a way that honors God.