content: In no way does this little card set replace books or experience, but for field use for common knots, (especially in a stressful situation) it's priceless. I've already needed it on so many occasions (work and around the yard), that I moved one of them from my BOB to my small EDC pouch. If you're anything like me, "kind of" knowing how to tie a specific knot can get you into more trouble than not having tied the darn thing in the first place! I had to secure some items for an typhoon and boy did this thing come in handy. *All* of my ropes and knots stayed tight unlike my usual post-storm assessment of finding them untied and strung out in the yard! Yes, you could probably make a set, but these are nicely printed on credit card like material (albeit a bit thinner) and are really legible and handy. If you have a BOB, this is a MUST have (especially for those you think you need 300' of 550 cord in your BOB).Four stars because I wish you could separate the cards for easier access.