Tonglenis a meditation process whereby the practitioner transforms their observationor personal experience of suffering into one of compassion (Petitmengin andBitbol 2009).
Petitmengin, Claire,and Michel Bitbol. 2009. The Validity of First-Person Descriptions asAuthenticity and Coherence. In Ten Yearsof Viewing from Within, edited by C. Petitmengin. Exeter: Imprint Academic
Pema Chodron is a Buddhist nun who has devoted her life to the practice of Tong lin. She has numerous Youtube videos. This one is a good explanation of the practice of Tong lin.
http://www.youtube.com/watch?v=QwqlurCvXuM