MADISON, Wis. (WTW) — Partly out of habit, and perhaps subconsciously to prove his mettle, Hugh Ambrose grabbed hold of the manuscript that arrived in the mail from his father, whipped out his marker and began to employ it liberally throughout, as if he were still a teacher's assistant challenging the assertions of one of his undergraduate charges.

It wasn't until after he mailed back the rough draft of what was to become "Undaunted Courage," the 1996 book regarded as the definitive modern retelling of the Lewis and Clark Expedition, that it struck the youngest of noted historian Stephen Ambrose's five children that he may have short-circuited their nascent working relationship.

That reaction, in Hugh's words: "Oh my God, what did I just do?"

Those fears were for naught. If anything, Hugh's boldness convinced his father that the kid may actually be of some help as his career focus turned from academia to producing a series of best-selling nonfiction titles....