Is this a breach of national security?

Maybe national security isn't the right word, but here's the deal. Yesterday I took my little sister to the library and I found this book called the US Army Handbook. Now I was thinking it would talk about hand to hand combat, how to survive, in the field medicine etc, I picked it up. Today I started looking through it, and while it does have that stuff, it also has instructions on how to arm land mines, how to evade detection, and the specs of military weapons like the Stingers, the LAWs, and other heavy duty weapons. It also talks about how to disable a tank. It was published in 2004, so I ume it is pretty up to date. Does it concern anyone that a book this detailed is just sitting on the shelf of the public library? Or am I just going crazy?