Mention Abhidharma - the 'ethical psychology' that was developed in the centuries after the Buddha - and eyelids start to droop - the repository of endless lists and categories that strips the magic out of the suttas and was roundly rebuked by Mahayanists for being overly-literal. The principal accounts of Abhidharma are dense academic tomes, list-bound translations or attempts to make it accessible that, for me miss the mark - Drinking the River Ganges and Know Your Mind are two that I've read. Meanwhile, the unprecedented interest in the relationship of Buddhism and psychology and countless self-help books connecting the two. But the Buddhist element in the psychology can be rather thin (Allan Wallace's books are an exception).
Subhuti's Mind in Harmony fills the gap magnificently, making Abhidharma ideas relevant and accessible. He achieves this by juggling the order in which the various elements appear, and for that reason, this isn't quite a guide to the Abhbidharma. But in doing so he makes all of the topics that are discussed immediately relevant to the brand project of mental transformation that is his theme.
Unlike Subhuti's other books, and probably because it has been edited from talks, the writing is crisp and lucid. that allows Subhuti's great qualities to shine - his conceptual clarity, this deep reflection and his intense engagement with the process of mental and spiritual life.
If I were to pick out a single section it would be the chapter on mindfulness, which offers an account of its broad meaning in Buddhist sources, and relates them brilliantly to the Abhidharma understanding of how the mind works.
Highly recommended for anyone who is serious about following the Buddhist path.