no not alll the books have the same characters or even follow along with the other books, I remember a clancy book that I read that was completely independent of the rest of the books.it was about the cold war coming to a war between us and the soviets, it was an excellent book but I cant remember the name.
Red Storm Rising is probably the one you're thinking of. Just to clarify, there are common characters and story threads through the "Jack Ryan" books, but Clancy has written (co-written, put his name on without writting, etc) many other non-Ryan books.