Tranquility of the mind and tranquility of the breath are inextricably linked. That is why many of the meditation approaches devised by Taoists use the breath as a vehicle for realizing the Way. Dr. Jwing-Ming Yang has published the excellent book, Qigong Meditation. Embryonic Breathing, which is an invaluable resource for understanding ancient documents which describe the meaning and intent of meditation breathing practices that have been historically employed by Taoist masters. He points out that the first goal is to attain a peaceful mind. Deep, profound breathing via the lower dantien is a means of achieving this goal. The lower dantien, centered in the body below the navel, functions as the major center for breath origin and circulation of energy up (Du meridian) and down (Ren meridian) the torso. This circulation helps regulate the spirit (shen) by cultivating space within the mind.
I was listing to an audio presentation by Dr. Wayne Dyer, a couple of days ago. This presentation is a part of his book, Getting in the Gap
A helpful resource for learning how to use the breath as a vehicle for transformation is the audio presentation by Bruce Frantzis, Tao of Letting Go
Use these methods to tame the monkey mind for obtaining psychological as well as spiritual maturity in your life. The world can use more people who are capable of using the power of tranquility to deal with the difficult situations that life sometimes presents us. And life regularly presents difficulties. These inner transformation methods are essential tools for helping us along the the Way, or Tao, and for seeing our difficulties as transient and possible sources of opportunity.