This month's book: Confessions on the 7:45 by Lisa Unger

Selena Murphy is commuting home on the train when she strikes up a conversation with a beautiful stranger in the next seat. The woman introduces herself as Martha and soon confesses that she’s been stuck in an affair with her boss. Selena, in turn, confesses that she suspects her husband is sleeping with the nanny. When the train arrives at Selena’s station, the two women part ways, presumably never to meet again.

Then the nanny disappears.

As Selena is pulled into the mystery of what happened, and as the fractures in her marriage grow deeper, she begins to wonder, who was Martha really? But she is hardly prepared for what she’ll discover…