The second of the Gray Man series and some of the character short comings of the first book begin coming into focus in the second. For the most part "On Target" moves very quickly and holds your interest from the very start. Unlike the first book this one ends fairly unsatisfyingly, however. The author seems to deliberately leave ends left untied, perhaps to use to pad the followup Gray Man book. I, personally, would prefer that glaring items find some sort of resolution in the book that I've invested my time, rather than being used to perhaps spike sales for the followup book(s). I'm probably going to continue on with the series anyway, and I've nearly talked myself into lowering my rating from 4-stars, to 3. However, the pacing, character development, and just the right amount of situation detail prompt me to leave my review at 4-stars.