The following resources are informative and easy to read.
Benson, H., & Klipper, M. Z. (1975). The relaxation response. New York: Morrow.
Farhi, D. (2000). Yoga mind, body & spirit: A return to wholeness. Macmillan.
Hanh, T. N. (2014). No mud, no lotus: The art of transforming suffering. Parallax Press.
Lasater, J. H. (2016). Relax and renew: Restful yoga for stressful times. Shambhala Publications.
Mehta, S., Mehta, M., & Mehta, S. (1990). Yoga: the Iyengar way. Knopf.
More (wonderful) resources:
Bouanchaud, B. (1997). The essence of Yoga: reflections on the Yoga sūtras of Patañjali. Rudra Press.
Iyengar, B. K. S., & Menuhin, Y. (1979). Light on yoga. Schocken Books.
Kornfield, J. (2009). A path with heart: A guide through the perils and promises of spiritual life. Bantam.
Prinster, T. (2014). Yoga for cancer: a guide to managing side effects, boosting immunity, and improving recovery for cancer survivors. Simon and Schuster.
“As wind drives away smoke and impurities from the atmosphere and its inherent quality is to burn and purify the area, pranayama is a divine fire which cleanses the senses, mind intellect and ego.”
-Iyengar, 2005, p. 58
Iyengar, B. K. S. (2005). Light on pranayama: the yogic art of breathing. Crossroad Publishing Company.
Chrysalides
: anything in the process of developing