This is a hard book to rate. I'm noticing a trend in novels that have been adapted from plays: odd pacing and structure, lack of detail/scene setting and a somewhat unsophisticated translation of emotional experience into words, which I imagine stems from the writer being so used to relying on actors to convey the inner world of the character. Prima Facie suffers on these fronts, yet overall it is an effective, affecting novel. On purely a literary level it is not a masterpiece but I think its strengths outweigh its weaknesses. I was continually drawn to it, I liked it and I would recommend it to others. 

*Probably worth noting I haven't seen the play it's based on.