"The great Indian Buddhist master Nagarjuna (1st - 2nd century A.D.) wrote his celebrated poem Letter to a Friend as a letter of advice to a South Indian king, and it has since become a monument in the Indian shastra tradition. Despite its short length (only 123 verses), it covers the whole Mahayana path, combining a practical approach to daily conduct with a theoretical exposition of the different stages leading to enlightenment. It has thus been...