Introduction to the Newman-Penrose Formalism

I am having trouble finding good introductory literature (e.g. a textbook or lecture notes) for the Newman-Penrose formalism of General Relativity.

I am looking for a resource suitable for someone who has read, say, all of Carroll’s book and the first part of Wald’s book, and who has skimmed a few of the advanced topics in the second half of Wald (e.g. I am familiar with congruences and optical scalars, singularities, causal structure, compactification, and black holes).