Paul's little letter to Titus is a masterpiece. It keeps the Christian focused on God's priorities. - it contains the gospel of salvation by grace through faith in the Lord Jesus Christ, it contains teaching for good living, and it contains nothing else!
But, some may object, where is the theology? Where is the prophecy? Where is the .....? Whatever place theology has, whatever place prophecy may have, whatever place anything else may have ..... all these come after the gospel and after the good works.
As Paul put it in Ephesians 2:8-10:
"For it is by grace you have been saved, through faith - and this not from yourselves, it is the gift of God - not by works, so that no one can boast. For we are God's workmanship, created in Christ Jesus to do good works, which God prepared in advance for us to do."
Titus, if you like, is an expansion of those three verses. It is the core of Christianity. It is one of the simplest books to read and understand, and the Christian's goal is to put it into practice.