I've mentioned Charles McCarry in this thread as had another, but I had never read his first novel The Miernik Dossier till now. What a fantastic novel.
Published in 1973 and set in around 1959, it's about several male and female covert agents from different countries and cultures who go on a road trip in a massive Cadillac from Switzerland to Austria and south to the Middle East, trying to keep their cover all the while. It's unlike anything I've read. Great characters. Good stuff. McCarry deserves far more credit.
One warning -- I couldn't find this one as an e-book, but some of his others are e-books. Just had to mention it.