The Four Noble Truths
From the preface: "This small booklet was compiled and edited from talks given by Venerable Ajahn Sumedho on the central teaching of the Buddha: that the unhappiness of humanity can be overcome through spiritual means. The teaching is conveyed through the Buddha’s Four Noble Truths, first expounded in 528 BC in the Deer Park at Sarnath near Varanasi and kept alive in the Buddhist world ever since."
"Venerable Ajahn Sumedho is a bhikkhu (mendicant monk) of the Theravada tradition of Buddhism. He was ordained in Thailand in 1966 and trained there for ten years. He is currently the Abbot of Amaravati Buddhist Centre as well as teacher and spiritual guide to many bhikkhus, Buddhist nuns and lay people."