Samantha Powers finished the Pulitzer Prize-winning “A Problem From Hell”: America in the Age of Genocide back in 2002, and since finishing that astonishingly-good book has written quite a few articles and advised Democratic presidential candidate Barack Obama. But she’s working on a new book as well, one that her job-related profile describes as “a political biography of the UN’s Sergio Vieira de Mello.” However, the info page accompanying a 2006 commencement speech of hers describes her next book as “on the causes and consequences of historical amnesia in American foreign policy.” I don’t know which one takes precedence - or whether they’re both describing the same project - but I have to say that the latter description sounds incredibly interesting.