Paul Allen is a rheumatologist, or a sort of detective of medicine. He sees patients whose symptoms elude diagnosis, and gives them the answers they're looking for: what's wrong, and by what mechanism, and, most imp0rtantly, can it be fixed? When his estranged adult son Daniel, the product of an earlier marriage, is arrested for assassinating a presidential candidate, Paul copes by trying to examine Daniel's life for symptoms in order to diagnosis and ultimately, fix him.
It's obvious from the outset that Paul's quest is futile, but Hawley is fascinating as he unravels the threads of Daniel's mildly dysfunctional childhood, interspersing the account with chapters about real-world assassins such as Sirhan Sirhan, Lee Harvey Oswald, and others.
It appears that Hawley cranked at least part of this out in the aftermath of the Gabrielle Giffords shooting in Tucson, which makes this engrossing novel a truly amazing feat for the speed of its production. Paul's grief and shame are almost excruciating in their realism. Not cheerful, but very good.