Opening to God: Lectio Divina and Life as Prayer (2010) by David Benner may challenge your understanding of prayer. Benner, a psychologist and spiritual guide, certainly acknowledges the necessity of petitionary prayer, but in this book, he presents an extended reflection on why prayer is not just that.
Building upon the ancient practice of lectio divina (sacred reading), Benner suggests several different ways in which the Christian's prayer life may be transformed. For those unfamiliar with lectio divina, it traditionally consists of 4 movements--lectio (reading), meditatio (meditation), oratio (prayer), and contemplatio (contemplation). It was developed as a way to engage holy scripture. Benner has expanded this idea into the world of prayer. The pray-er may engage in several different practices including: prayer as attending, prayer as pondering, prayer as responding, and prayer as being. As he describes how each of these approaches may be practiced, he shatters the notion of prayer simply as supplication.
There is much to commend about this book. I think many Christians, like me, have a stunted concept of prayer. Opening to God will assuredly push your boundaries of understanding what a life of prayer can look like. On the other hand, Benner's apparent full acceptance of the contemplative tradition including "emptying ourselves" seems at times to have more connection with Eastern spirituality than with orthodox Christianity.
On the whole, I would happily commend this book for those who feel stagnant in their prayer lives and hope to grow in relationship with God.