[...] From biblical times to the present day, the most common and simple form of prayer is the direct invocation of man to God for Him to hear his request. This prayer is born out of our need to come into communion with God, to feel His presence and love within us, to receive help and guidance. It doesn't matter if we pray inside a temple or alone in our homes. It doesn't matter if we observe a ritual or if our prayer is spontaneous. What matters is our faith that our prayer will be heard.
[...]
(from the book's preface)