Scholars of Sanskrit give us various meanings for the word Prana including breath (or life-force), energy, spirit and soul. A simple meaning of Pranayama is breath control. An important text in Hindu tradition compiled prior to 400 CE, The Yoga Sutras of Patanjali, describes the theory and practice of Yoga. The section on practice, or Sadhana Pada, describes Pranayama – breathing techniques to control the prana or life force – as the fourth of eight branches or limbs of Yoga, preliminary to the subsequent branches of withdrawal of the senses and concentration.