Satyarth Prakash (Light of Truth) by Maharishi Dayanand Saraswati, founder of Arya Samaj [in Hindi]

Excerpt from vedicbooks.com:
The book enshrines universal truth of universal human values in a spirit of universal love & justice. A study of the book will give a clear insight into all the important theologies and metaphysics that one finds prevalent in India. It can be ranked with the top ranking Holy books of the world.

Satyartha Prakasha is an exposition of Truth, Dharma and Revelation in the modern context. Swami Dayananda referred back to the permanent message of the Vedas and exhorted the Indians to renew and rebuild their life and culture in new forms which were relevant in the new age. It is an interfaith dialogue on unity of faith in the diversity of religions, beliefs and practices. Second part of Satyartha Prakasha has often been criticized be those who have misunderstood Swamiji’s purpose and intention. Swamiji himself says in the ‘Introduction’: “I do not mean to hurt or oppose anybody. My purpose is to state the universal truth and distinguish if from what is not true.” Satyartha Prakasha deserves to be read carefully with understanding and open mind from cover to cover.