I’ve been reading Leonardo Boff’s work Trinity and Society. Boff is a Roman Catholic liberation theologian who may or may not be a Marxist. This is perhaps the most thought-provoking book on the Trinity I’ve yet read; right up there with Jurgen Moltmann’s Trinity and the Kingdom. Both these gentlemen are social trinitarians. They had a formative influence on Millard Erickson’s own monograph on the Trinity, which is excellent.