I had only a vague idea of who Richard Holbrooke was when I picked up “Our Man,” the biography by George Packer (Alfred A. Knopf, $30) that came out in May. But I was hooked after the first paragraph — maybe after the first sentence. (“Holbrooke? Yes, I knew him.”) Holbrooke — brilliant and idealistic early on, difficult and egotistical later — was an American diplomat perhaps best known as the stubborn brain behind the Dayton Accords that ended the Balkan war. He started out in Vietnam, died while trying to solve Afghanistan, and did his best to have his fingers in every international pie in between. Packer’s writing is lively and quick, packed with voice and with asides to the reader that only add to his credibility. Read it for the first 150 pages alone — the best primer on Vietnam you’ll find.