Originally published under a pseudonym, The Road To Gandolfo is unusual for Ludlum in that it's a comedy novel. And, as such, I find it much more appealing that his serious thrillers, and it's the book of his that I've re-read the most times.
The plot concerns an epic con undertaken by an ex-Army General. It's not particularly intricate but there's lots of entertaining detail. And it's not too heavyweight, either - unlike such back-breakers like the Jason Bourne novels.
All in all, one of his lesser known books but worth finding.