A leading scientist in the Manhattan Project, who disappeared in protest after the first bomb was dropped on Japan, has returned with a befuddled mind talking of dozens of suitcase atomic bombs planted in major cities across the U.S. Charlie Sparrow is a major player in the team to find the truth and the nukes.
Tom Ardies was a parliamentary correspondent and columnist for the Vancouver Sun during the 60's. In the 70's he wrote several suspence thrillers, the first three being the Charles Sparrow series. A later book, Kosygin Is Coming, was turned into a movie called Russian Roulette starring George Segal and Denholm Elliott.
Although this was published in 1972, the premise of nuclear terrorism still works even if there might be a couple of new players. You must pay close attention to the plot as it has more twists and turns than a road in the Himalayas but although it is a treacherous trek, it is well worth it. I just hope the book doesn't give the bad guys any ideas!