Summary: , the Aurobindo Birth Centenary Library Volume 2 presents a comprehensive exploration of the perfection of the mental being, the instruments of the spirit, purification of the lower mentality, intelligence and will, liberation of the spirit and nature, elements of perfection, equality, and the divine Shakti. Through the synthesis of yoga, Aurobindo emphasizes the importance of knowledge and works in attaining conscious oneness with the divine being, leading to perfect love and unity. The text delves into the integral perfection of the human soul through the purification of all complex instruments, the development of spiritual powers, and the transformation of the human nature into an instrument of divine knowledge, will, and joy. Aurobindo highlights the significance of equality, self-mastery, and unity with the divine in achieving a spiritual liberation that transcends sin, virtue, and limitations of the ego, ultimately leading to the integral liberation of the spirit and nature into a divine quality and power of world-experience, fulfilling the aim of human existence in all its parts.