There are many books on prayer but in today's Gospel we have Jesus' own teaching on prayer from the Sermon on the Mount.
I met an Irish Jesuit priest who impressed me by knowing this text off by heart. I have tried to do the same.
At the heart of Christian prayer is the knowledge that God is Our Father.
I don't need to say anymore, The Lord has said it all.
Let us not complicate prayer but follow the Lord's way.