I picked this up for £1 in a bookshop yesterday and have been reluctant to put it down since I started reading it. It is quite simply brilliant.
The Spiritual Life: a treatise on Ascetical and Mystical Theology- Very Rev Adolphe Tanquerey SS, DD
As a scientist, I'm happier reading text books than story books or touchy-feely "my experience" books. This is a text book on the science of the Saints. It is just the best resource I have ever seen for growing into your faith. It puts everything together in a coherent framework, showing the relationships between the Creator and the created and comprehensively goes through your life and your relationship with God.
Book 1: The purification of your soul (the purgative way)
Book 2: Progress in the Christian virtues (the illuminative way)
Book 3: the unitive way - the Holy Spirit and Infused Contemplation
It draws on all the major Catholic contemplative traditions.
A dry read, but an illuminating and beautiful one nevertheless.
I think Tan books have a current edition of this.
My copy has the words "ora pro Mr. Barton" written in the front, and that I will do.