A 47-year-old mystery finally may be resolved. Grand Rapids-based publisher Principia Media announced yesterday it has released a book that allegedly reveals the real identity of “D.B. Cooper,” the infamous skyjacker who in 1971 demanded a $200,000 ransom on board a flight from Portland, Oregon to Seattle’s Sea-Tac airport, before jumping 10,000 feet to his escape. The book, “D.B. Cooper & Me: A Criminal, A Spy, My Best Friend,” is by Carl Laurin, an alleged friend of the skyjacker, and details an investigation into Cooper’s identity. Laurin claims that Cooper was the late "military paratrooper, daredevil and intelligence operative" Walter R. Reca, Principia Media said. Reca,...