I've read Strachan's book of Clausewitz's Art of War. It is the best of all scientific studies altogether that I've ever read, and a good example of one if you're about to study things of any topic. The book is comprehensive with a mass of information although it is short and easy to read! :-)
While I understand the reasons for General Sir John Hackett's books having fallen out of favour I think this is myopic. Given that the world came within hours of world war 3 on a number of occasions, and given just how authoritative the list of contributing authors was, I feel that The Third Wold War and its sequel are still entirely relevant to strategic thinking.
"Why don't more people enjoy learning?" Because no one likes to be brought face to face with their own ignorance. You need to be made aware of your own lack of knowledge before you can work on correcting it. Far too many would love to believe they were born knowing everything.