[esbeeb]

Meditation, of course. The Brahmavihara of Karuna (compassion) is exactly what you are looking for here.

[rramadass]

1) https://en.wikipedia.org/wiki/Brahmavihara

2) https://en.wikipedia.org/wiki/Karu%E1%B9%87%C4%81

[esbeeb]

As to a book recommendation, the Buddha's "Early Buddhist Texts" (of the Pali Canon) are highly recommended. There's a lot of material there, but well worth reading, IMHO.