Once again Heather O’Neill proves her ability to cut deep. When We Lost Our Heads is an invigorating, frustrating, dark, beautiful, terrible tragedy. As much as I loved Lullabies for Little Criminals, I think if I went back and reread the book for a third time I would be more critical of it now—both because I’m older and because O’Neill’s writing has improved since then. When We Lost Our Heads displays a mastery over…