The Satyarth Prakash (The light of Truth) is the masterpiece of Swami Dayanand Saraswati.  

• As the great writer of this masterpiece Swami Dayanand was a symbol of ultimate morality and spiritualism and was a sage of standing.  
• This book (Satyarth Prakash) is, indeed, and encyclopedia of the various contemporary social religious and political currents cross-currents and movements going on at the time of the writer’s life.  

• To go it further, the writer has not spared the past events and guiding philosophies, which has polluted the human mind and deteriorated the man’s quest for true knowledge and right way of life. 

Source: Spectrum’s A Brief History of Modern India.