Pocket Prayers: 40 Simple Prayers that Bring Peace and Rest by Max Lucado
This is a short little collection of prayers (about 40), covering various topics, each of which starts with a Bible verse. If you are new to prayer, I think it’s a good place to start. The prayers are not complicated or verbose. I would not say that it is an essential part to a Christian library, but if you are looking for a simple collection of prayers, it is not a bad little book.