Guru Nanak Parkash
Guru Nanak Parkash is a book written by Bhai Santokh Singh in about 1823. Sri Guru Nanak Prakash, an epic poem consisting of 9,700 verses dealing with the life and teachings of Guru Nanak. About the middle of nineteenth century the printed copies of this Prakash were available to the people in decent numbers. Probably this was the first book easily obtainable by the masses. Previously only the wealthy could attain hand-written and calligraphed copies.
Bhai Santokh Singh's primary source of information was the Janam Sakhi of Bhai Bala. On the basis of the knowledge he acquired from this Janam Sakhi he initiated Puranmashi of Kartik, Sambat 1526 (about November 1469 AD) as the date of birth of Baba Nanak. Apparently, first time in history, this caused the celebration of the Birthday at Nankana Sahib in 1853, in the month of Kartik. Subsequently this became the most revered date in the Sikh Chronology.
Bhai Santokh Singh, (8 October 1787 - 19 October 1843) the noted author of six important literary works - Naam Kosh, Guru Nanak Parkash, Garb Ganjni Teeka (teeka means translation and explanation of a work), Balmik Ramayan, Atam Purayan Teeka and his magnum opus, Sri Gur Partap Suraj Granth aka Suraj Parkash, was born on 8 October 1787. He was the son of Bhai Deva Singh and Mata Rajadi, professional cloth printers of Nurdin village, also known as Sarai Nurdin, 7 km northwest of Tarn Taran in Amritsar district of the Punjab.