As you may already have read in my biography,
Tom Clany is currently my favorite author. I try real hard to real all of his
books. Without doing too much advertisement here I would like to explain what I
like so much about his books and what they are about.
On the one hand there is this realistic touch. Though all of his novels are "fiction", of course, one constantly has to wonder where the border between reality and fiction is. This is what is typical for his stories: They take place in the whole world, it is always about America's intelligence agencies and it's government and, of course, it's military. I do not know the American system that good, but my impression is that most of the things Clancy describes are not that far off. Most of his novels are about a conflict between nations which will nearly always end with some kind of war or special operation. They are about human nature, conspiracies, war, death and heros.
On the other hand what I like is that his stories can be connected to each other. They tell a more or less continuous tale of the world during and after the Cold War. The two protagonists (at least one of them is in each story) are John Patrick Ryan and John Terrence Clark, maiden Kelly (this series of books is sometimes called the Ryanverse). They are both very strong and different personalities and one gets to know them quite good through the years which makes their adventures even more interesting.
To make it easier for a new Clancy fan, I will try to sort his most important books in the chronological order of the story told. This is not equivalent to the order in which Clancy wrote them. When I read those books I didn't knew the order, I survived it, but it's much more fun to understand all those hints given in the various books. Well, here's the list:
From my point of view it is especially important to read "Debt of
Honor" and "Executive Orders" in the correct order since the
second starts exactly where the first ends.
Tom Clancy wrote much more (even non-fiction), but I have to admit that till now I have not read all that much of his other work. Here are the other titles I have read. You cannot give them an order since they are not related to each other.
A personal note: Though I'm a native German, I read all of his books in English. This has to reasons mainly: First it's good for my English skills, and second (which is much more important) I just like them more in English. I once read some pages of the translation in a store and, well, I just didn't like it. It just wasn't the same any more, sorry, I can't explain it any better.
Spoiler warning: In the next paragraph I will tell some of the things that happen in Clancy's books. If you'd like to learn it all by your self I strongly recommend to skip to the next paragraph.
Ryan is Clancy's intelligence specialist. I think that he was born as the
son of a police officer in Baltimore between 1950 and 1955. He had his first
contact with the military as a young marine. Additionally he has got an PhD.
in history (seems to be a real passion for him), a subject he gave lectures
in, too. Together with his wife (MD Cathy Ryan, a gifted surgeon specialized
in opthamalogical surgery) he has four children, two daughters and two sons.
After an assault by terrorists on his family (in Patriot Games - here he gets
his "Sir", too) he became part of the CIA where he turned out to be
a brilliant analyst quickly working up his way there. After Admiral James
Greer died, who was some kind of second father to Ryan, he becomes the new
DDI, the Deputy Director (Intelligence).
All of this does not mean that he is a "suit" just sitting behind his desk. Several times he put his life on the line: In "Patriot Games" he defended his family against terrorists, in "The Hunt for Red October" he had to kill a spy, in "The Cardinal of the Kremlin" he helped the head of the KGB to defect which nearly got him killed and in "Clear and Present Danger" he sat behind a machine gun during a rescue mission somewhere in the jungle.
After some time Ryan got the new NSA (National Security Adviser) where he worked for the President. However, his career did not stop there, in "Executive Orders" he became President himself and had to protect the USA against a serious threat. During all this time, Ryan sticked to his ideals and did not refrain from a good argument.
For more information on the Ryan family have a look at the ClancyFAQ.
Kelly is a completely different type of guy, he is the right man for really
wild and dangerous missions. I think that he was born between 1942 and 1948.
As a young man he joined the SEALs (Sea Air Land) which is one of the finest
and toughest special operations force of the marines. He is a very tough guy
and always in a superb shape. After his first missions in Vietnam he lived
peacefully together with his wife, working as a diver.
But then his wife died in an car accident and Kelly got to know Pam. However, Pam had problems and got killed by drug dealers. This brought Kelly on the scene who wanted his revenge in "Without Remorse". He actually killed several people and the CIA recognized him. Together they arranged his "death". John Kelly died only to be reborn as John Clark. During this story he also met his new wife, Sandy O'Toole. She gave birth to his first child, which later married his partner Domino "Ding" Chavez.
Some years and many missions later (in the mean time, Ryan and Clark met each other and became friends) he became the leader of an international anti-terror force, Rainbow Six. Together they saved the world once again during the Olympic Games 2000 in Sydney.
Though Ryan and Clark each have their own books, they work together quite a lot, too. Their first encounter was in "Patriot Games" but that was not personal. They became friends in "Clear and Present Danger" during a rescue mission which became the starting point of their mutual work.
A good starting point is the Tom-Clancy-FAQ where you can find much additional information to his books and the whole background.
Additionally there exists this newsgroup: alt.books.tom-clancy, where Clancy fans meet each other from around the world.