Who is Peter Jordan from The Unlikely Spy and what is their importance?

Peter Jordan is an American engineer who was originally married to Margaret Lauterbach, a wealthy woman from New York. Before the war began, Margaret, pregnant with their second child, is killed in an automobile accident. Jordan throws himself into his work, and becomes well known for building unique bridges and fortifications. When the Allied forces plan their invasion of Normandy, a particularly clever engineering feat will be required, and Jordan is brought to England to work on it.