The Yoga Sutras of Patanjali is a foundational text of classical Yoga philosophy. It consists of 196 short aphorisms or sutras that are organized into four chapters or books, known as padas. The text is written in Sanskrit and dates back to around 200 BCE to 400 CE.
Book One: Samadhi Pada The first book discusses the nature of Yoga, the various types of mental modifications or vrittis, and the practice of Yoga. Patanjali defines Yoga as the cessation of the fluctuations of the mind. He describes the five types of vrittis: correct knowledge, misconception, imagination, sleep, and memory. He also outlines the eight limbs of Yoga: yama (ethical restraints), niyama (ethical observances), Asana (postures), Pranayama (breath control), pratyahara (withdrawal of the senses), dharana (concentration), dhyana (meditation), and Samadhi (absorption).
Book Two: Sadhana Pada The second book discusses the practice of Yoga in more detail. Patanjali explains the obstacles to Yoga, known as the five kleshas: ignorance, egoism, attachment, aversion, and fear of death. He also describes the techniques for overcoming these obstacles, including the practice of kriya Yoga, which involves tapas (discipline), svadhyaya (self-study), and ishvara pranidhana (surrender to a higher power).
Book Three: Vibhuti Pada The third book discusses the powers or siddhis that can be attained through the practice of Yoga. Patanjali explains that these powers are not the goal of Yoga, but rather distractions that can hinder progress. He also discusses the relationship between the mind and the external world, and how the mind can be trained to perceive reality more accurately.
Book Four: Kaivalya Pada The fourth book discusses the ultimate goal of Yoga, which is kaivalya or liberation. Patanjali explains that liberation is achieved when the practitioner realizes the true nature of the self and transcends the limitations of the ego. He also discusses the various paths to liberation, including Jnana Yoga (the path of knowledge), Bhakti Yoga (the path of devotion), and Karma Yoga (the path of action).
Overall, the Yoga Sutras of Patanjali provides a comprehensive guide to the practice and philosophy of Yoga. It emphasizes the importance of ethical conduct, mental discipline, and spiritual realization in achieving the ultimate goal of liberation.