A childhood visit to Antietam kindled a lasting interest in the Civil War. I studied history in college, decided without much enthusiasm to make my living as a lawyer, and then went back to school to study the Civil War for real.

As a graduate assistant for David Herbert Donald’s biography Lincoln , I was given a list of hundreds of “I saw Lincoln” articles to find in obscure nineteenthcentury periodicals, and in the course of collecting and reading those accounts of Lincoln from life, in the stacks of Harvard’s Widener Library, I “met” the man. I had left the law partly because I had found no role in the profession; had I met Lincoln sooner, I might still be a lawyer.