Sri Yukteswar Giri, also known as Yogiraj Sri Yukteswar Giri, was a highly revered spiritual teacher and guru of Paramahansa Yogananda. He was a disciple of the great saint, Lahiri Mahasaya, and played a significant role in spreading the teachings of Kriya Yoga to the western world. Sri Yukteswar's teachings revolve around the concept of "Self-realization" and the path of Kriya Yoga, which leads to the ultimate union with the Divine.

To learn more about Sri Yukteswar and his teachings, one can start by reading his book, "The Holy Science." This book is considered to be his most significant work and provides a comprehensive understanding of his teachings on spirituality, science, and the evolution of the soul. It is a must-read for anyone interested in delving deeper into Sri Yukteswar's philosophy.

Apart from his book, there are numerous resources available online that offer insights into Sri Yukteswar's life and teachings. The official website of Self-Realization Fellowship, founded by Paramahansa Yogananda, has a dedicated section on Sri Yukteswar, which includes his biography, teachings, and quotes. The organization also offers various online courses and webinars that delve into his teachings in detail.

The books and lectures of Paramahansa Yogananda also provide valuable insights into Sri Yukteswar's teachings. Being a disciple of Sri Yukteswar, Yogananda has beautifully elucidated his guru's teachings in his works, such as "Autobiography of a Yogi" and "The Second Coming of Christ: The Resurrection of the Christ Within You." These books are considered spiritual classics and are a great source to understand Sri Yukteswar's teachings from the perspective of his most famous disciple.

One can also visit the ashram of Self-Realization Fellowship in Encinitas, California, where Sri Yukteswar lived and taught for many years. The ashram has a meditation garden dedicated to him, and visitors can also attend lectures and classes on his teachings.

Furthermore, there are many spiritual organizations and centers that follow the teachings of Sri Yukteswar and offer courses, workshops, and retreats to learn more about his philosophy. These organizations also have online resources, including articles, videos, and podcasts, that provide a deeper understanding of his teachings.

In conclusion, there are various ways to learn more about Sri Yukteswar and his teachings, including reading his book, exploring online resources, attending lectures and classes, and visiting his ashram. However, the most important aspect of learning about Sri Yukteswar is to approach his teachings with an open mind and a sincere heart, as his teachings are meant to guide individuals on their spiritual journey towards self-realization.