Loving-kindness, or Metta, is the Buddhist practice of inclining the mind towards goodwill.
When I wanted to add this quality to my mindfulness practice, my friends instantly recommended that I read Sharon Salzberg. This is the book that I started with.
Sharon Salzberg is one of the founders of the Insight Meditation Society, which seeks to bring the teaching of the Buddha to the West, without the culture clash of Buddhist religion.
This is what should be done, by those who are skilled in goodness, and who know the path of peace.
The Buddha – from the Metta Sutra