The Aṅguttara Nikāya is the fourth of the major Nikāyas of the Sutta Piṭaka of the Pāli canon. It presents the teachings of the Buddha arranged in a way more common in ancient times and in oral/aural cultures than in the contemporary West. These suttas are grouped by reference to numbers; for example, we have three kinds of purity, four qualities that make a difference, et cetera. The Numerical Discourses (aṅguttara means “increasing-by-a-factor,” loosely translated as “Numerical Discourses”) begin with Ones and run through Elevens.
Of course, the teachings of the Aṅguttara Nikāya are themselves vastly more important than the numerical arrangement scheme. These teachings are intensely focused on practice. They include topics such as family life, livelihood, friendship, getting along in community, growth in wisdom, training the mind, and techniques of meditation. We find every kind of person interacting with the Buddha; his responses to them are couched in a correspondingly rich range of similes.
Translator Bhikkhu Bodhi provides an excellent Introduction to the volume, along with notes, appendices, a Pāli-English glossary, and bibliography to help the reader.