This was a good and interesting book, but not one for the person unfamiliar with Biblical criticism. If you have not read "The Interpretation of the Bible in the Church" (Pontifical Biblical Commission, 1993) I would suggest that you read that first. Also, a strong grounding in historical criticism is a must to understand the other forms of critical interpretation that this author engages in. And given that this book is about a particular event in Mark, knowing Mark's gospel of course is necessary.
I find his psychological criticism an interesting approach to modern (and social) application of the Biblical text. I would put this under a mix of social and literary (narrative) criticism, so I do see it as secondary to historical criticism, but an import part of the conversation to see how the text impacts us in modern times.