Immersing yourself in the world of a psychopathic killer might not be your idea of fun, so Dick Lehr and Gerard O’Neill have gone and done it for you. In their book Whitey, they unpack who Whitey Bulger was, what made him that way, and how he subverted a major anti-crime initiative by recruiting agents to his side.

Lehr and O’Neill are on familiar turf with this book, in more ways than one. Both were once writers for the Boston Globe, and this is their second book on Bulger, Boston’s criminal mastermind and mob boss. The first was the bestseller Black Mass, which focused on Bulger’s relationship with FBI agent John Connolly.

In Whitey, they run the full length of the track, starting well before Bulger was born and leading up to his recent capture following the sixteen years he spent in hiding. Whitey is not just the story of the titular figure, but of the world he came out of and the era his life spanned. To explain Bulger, the authors explain Boston. They focus on the particular region of Southie, which is both Boston and not Boston, and the surge of Irish immigration that defined the city.

Lehr and O’Neill have spent a lot of time and spilled a lot of ink on Bulger, but they haven’t been seduced by their subject. Their book is clear-eyed and insightful, free of illusions about Bulger’s bad deeds and unmoved by whatever allure Bulger must have had to build the small empire that he did.

There might not be any way to really explain the sickness that possesses men like Bulger, but Whitey delivers the closest possible path to understanding.