This volume contains 9 thoroughly refereed and revised papers detailing recent advances in research on designing trading agents and mechanisms for agent-mediated e-commerce. They were originally presented at the 12th International Workshop on Agent-Mediated Electronic Commerce (AMEC 2010), collocated with AAMAS 2010 in Toronto, Canada, or the 2010 Workshop on Trading Agent Design and Analysis (TADA 2010), collocated with EC 2010 in Cambridge, MA, USA. The papers examine emerging topics such as ad auctions and supply chains, or the interactions between competing markets, and present novel algorithms and rigorous theoretical results. Several of them evaluate their results using real data from large e-commerce sites or from experiments with human traders.

In "The Assassin's Accomplice," historian Kate Clifford Larson tells the gripping story of Mary Surratt, a little-known participant in the plot to kill Abraham Lincoln, and the first woman ever to be executed by the federal government of the United States. Surratt, a Confederate sympathizer, ran the boarding house in Washington where the conspirators-including her rebel son, John Surratt-met to plan the assassination. When a military tribunal convicted her for her crimes and sentenced her to death, five of the nine commissioners petitioned President Andrew Johnson to show mercy on Surratt because of her sex and age. Unmoved, Johnson refused-Surratt, he said, "kept the nest that hatched the egg." Set against the backdrop of the Civil War, "The Assassin's Accomplice" tells the intricate story of the Lincoln conspiracy through the eyes of its only female participant. Based on long-lost interviews, confessions, and court testimony, the text explores how Mary's actions defied nineteenth-century norms of femininity, piety, and motherhood, leaving her vulnerable to deadly punishment historically reserved for men. A riveting narrative account of sex, espionage, and murder cloaked in the enchantments of Southern womanhood, "The Assassin's Accomplice" offers a fresh perspective on America's most famous murder.