Most of us have seen the movie. I became interested in the Jack Ryan series due to the mini-series and started reading the novels as I can get them - not necessarily sequentially. I was going to skip "Patriot Games" because I saw the movie. That would have been a mistake. It's a fine read and not quite the same story as the movie. It also introduces and further defines existing characters that you'll come across in later books. If you only read a few Clancy Novels, this should be one of them.