As a biographer, I have concentrated on the nineteenth century. Everyone in my books is long since dead. If they published anything, it's public domain now. But my books aren't.
Laying claim to the past is a tricky thing. The subject himself belongs to no one. Anyone could release a book or movie or television series about Cornelius Vanderbilt or Jesse James without asking my permission. But there's a distinct line between what is public domain, and what belongs to the biographer. There's a great deal of authorship involved in any biography, no matter how old or well known the subject. The greater the originality and depth of work, the greater the author's claim to intellectual property rights.
That work can loosely be broken down into three overlapping categories: research, analysis, and narrative.
First, research. Let's take the hypothetical case of a biography of Bill Clinton—a very public figure, whose public acts (and many private ones) were reported by multiple news outlets. If a biographer were to base a book on these easily available and highly redundant sources, then the information presented would not be the author's property. A director could release a film depicting the same events, without buying the movie rights to that biography. But once the author starts to conduct original, unique research—say, by uncovering a stash of letters Clinton had written to a college girlfriend—then the information derived from that research becomes the property of that author. Want to make a movie about Clinton and his college flame? You've got to pay for the rights.
In the case of The First Tycoon, my subject was famous, even iconic. Yet I discovered entire continents of new information in every period of his life, by carrying out research that no one had ever performed before. The broad shape of Vanderbilt's life was well known long before I took up work. But once you get into any kind of detail, then you either rely on my original research or you'll likely get it wrong. And by "detail," I don't mean microscopic stuff. Some of it is big, from businesses he started that no one knew about before, to his relationship with various U.S. presidents.
But it's important to stress that research isn't that simple. You don't just discover self-contained facts in the archives, anymore than you mine for diamonds, and dig up pre-cut stones ready for the ring. Usually multiple discoveries have to be pieced together and analyzed, based on a deep understanding of the historical context.
For example, I found a letter showing that Thomas Gibbons hired Vanderbilt as his steamboat captain entirely by accident (overturning existing ideas of how they started to work together). A clean, self-contained discovery, right? Wrong. To make any sense out of it, I had to dig into his other business operations, and found that Vanderbilt never fully sacrificed his independence while working for Gibbons. He was more a junior partner, or perhaps a senior executive, with great authority and independent investments of his own.
More than that, my research, reading, and thinking about the episode convinced me that Vanderbilt and Gibbons were involved in far more than a business battle. The conflict they waged represented an attack on the eighteenth-century culture of deference, and was part of the emergence of a more competitive, individualistic society. New knowledge emerged through my original research; but its full meaning only exists because of how I analyzed its significance. On both counts, this is the sort of thing that makes my account of Vanderbilt's story intellectual property, rather than general knowledge.
So much for research and analysis; there remains narrative. A story never tells itself. I had tens of thousands of sources and notes. I deliberately crafted them into a narrative, consciously attending to pacing, the creation of expectations, the various subplots, and the development of characters.
Take, for example, Vanderbilt's relationship with his son-in-law, Horace F. Clark. Clark was one of the Commodore's most important assistants for much of his career, rising from struggling attorney, handling tedious minor cases, to Vanderbilt's representative in Congress, to chief of the Lake Shore Railway, which he ran on the Commodore's behalf. Some of these facts I discovered; others were previously known. But I developed Clark's personality, his close relationship with two other Vanderbilt assistants (Augustus Schell and James H. Banker), his growing ambition, and his ultimate betrayal of Vanderbilt into a major part of my book. Clark emerges as a real person—and drives the action along—only because of my deliberate efforts. I not only dug up new facts, I made choices as a writer that make my treatment of Clark fuller, more complex, and more integral to the narrative momentum than in any previous book about Commodore Vanderbilt.
Well, some readers might disagree that I succeeded in my efforts. My point is not to praise myself, but to emphasize that Clark, in my book, is very much the product of my creative efforts as a writer. Just because my portrait is nonfiction does not diminish my intellectual property rights to that portrait.
I've just explained at length how a nonfiction historical account is still the writer's property. But what if an author does sell the rights for an adaptation? My message to writers is hands off. You haven't bought the rights to control the film, TV series, or play; you've sold the right for the adapter to use your book as the starting point. The purpose of an adaptation is not to be as faithful as possible; it should succeed on its own terms, as a work of art and entertainment. It's an irony that some of the most accurate adaptations of books have made lousy movies, while some films that have taken great liberties with a book have been spectacular.