Miracle of Mindfulness. A very nicely written contemplation of the importance of mindfulness and how to do it. It's technically a very easy read, as most buddhist writings are, but it's extremely deep and full of knowledge. A very worthwhile purchase, no matter what you're struggling with.
Wherever you go, there you are Another very nice contemplation on mindfulness and acceptance from a very well-respected therapist. A nice companion to therapy.