Fr. Bernard Lonergan's writings have not so far received much discussion in British philosophical journals, although they contain one of the most fully-developed contemporary presentations of Catholic Christianity and have a substantial and distinctive philosophical content. They have not lacked theological commentators, both in print and in conferencediscussions. The present article has three aims: to draw attention to Lonergan's work and its philosophical relevance; to notice the publication of his latest book, Method in Theology, and to venture some critical comments on certain arguments about the intelligibility of being, being and the good, and God, in his book Insight (published first in 1957). These arguments are central to Lonergan's account of theism, a theism which, in its orthodox Roman Catholic form, is presupposed by Method in Theology. The books are organically interrelated. One admirer of Lonergan described the newer book (before its appearance) as ‘the book [Lonergan] originally set out to write’.