Retiring history professor Perry Gregson wonders whether it had to be this way. Should he have known to turn down a semester abroad so he would have been with his chronically ill little sister when she passed away? Could he have avoided turning her death into a template for severing his romantic bonds? The Use of Regret is Perry's eternally recirculating journey through the truths and fictions and fantasies of his life, a trek that points up parallels between the human mind and the United States, each of which is simultaneously a single entity and a constitution of hundreds of millions of...