World War Z by Max Brooks written as a series of bite size stories that tell a chronological Zombie War. Easy to read, really enjoyable, much, much, much better than the film that uses the same name.
If you're of a science bent, The Martian by Andy Weir, easy reading funny at times and tries for semblance of scientific accuracy better than the film but the film really did it justice given the limitations of the format versus books.
If you're thinking Clancy you can't go wrong with the original Jack Ryan books starting with Patriot games not first released, but before Hunt for Red October in timeline. Probably can pick them up v cheap in charity shops.