On a January night in 1610 a professor of mathematics in Padua pointed ahomemade glass at Jupiter and saw three small stars beside it. Other men had looked. He wrote down where they were and came back the next night to see whether they had moved. They had, and a fourth appeared a week later.

Within a year he had a court title, a philosopher's salary and no students to teach. Within six he had been told to stop. Within twenty-three he was on his knees before the Inquisition, and the charge was not the moons and not the sun. It was a book.

Rome had let him write it on conditions. One was that the pope's own argument had to be in it: God could produce the world we see by means no man could guess, so nothing we observe can ever prove how it is really put together. Galileo obeyed. He put it on the last page, in the mouth of Simplicio, the plodding Aristotelian who has lost every exchange for four hundred pages. Nobody in Rome had to be told whose argument it was.

And under all of it the question he sharpened for everyone who came after and then answered badly for himself. What counts as proof? The glass gave him proofs, of moons and of phases. The proof he staked his life on was something else.

Governor Walter Edge and the New Jersey Machine He Joined, Broke and Erased

On Boardwalk Empire he is a supporting player in a good suit. In the Bridgegate scandal, “Wally Edge” is the alias a political operative wore while helping jam the George Washington Bridge, which is run by the agency Edge built. Twice in twenty years New Jersey reached for his name, and neither time did anyone know what they were holding.

He was governor of New Jersey twice, a United States senator, and ambassador to France between the wars. He broke the deadlock that built the Holland Tunnel and the Benjamin Franklin Bridge.

Then at seventy he came out of retirement to break the most powerful political boss in America, and set in motion the greatest overhaul of New Jersey government in its history.

He got there the way everything got done in New Jersey. By a deal. In 1916 the Republican boss of Atlantic City and the Democratic boss of Jersey City, who agreed on nothing else, agreed on him.

David Stevens is an engineer and historian whose books begin with a simple question: what does the surviving record actually say?

His subjects range from Galileo's confrontation with the Inquisition and the ideas of Darwin, Adam Smith, Machiavelli and Confucius to the forgotten political career of New Jersey governor Walter Edge and the lives of his own ancestors.

Stevens spent his career in systems and software engineering. That background shapes the way he approaches history: follow the evidence, distinguish what is known from what is inferred, and tell the story without pretending the gaps in the record aren't there.

He is the author of Which Exit?, The Printer's Son, Iron & Thread, Galileo Galilei: What Counts as Proof, and other works of history and historical fiction.