A handly little booklet of 6 plastic 2-sided cards featuring 23 knots that are useful for all kinds of outdoor applications. The cards are held together with a biner through a brass eyelet - completely waterproof. Clip these to your backpack so you are ready for anything from tying tarps, securing boats on your rooftop, or survival situations.

Knots included:

Bowline (the single best all-around knot to know)
Square Knot, Water Knot
Rolling Hitch, Clove Hitch
Sheet Bend, Double Sheet Bend
Trucker's Hitch (a must-know knot!)
Mooring Hitch, Cleat Hitch (a boaters must-know knot)
Tautline Hitch, Buntline Hitch (for attaching rings etc to rope)
Prusik Knot (good for bow lines on a vehicle)
Butterfly Knot, Half Hitch, Two Half Hitches
Constrictor Knot (bundle up loose items)
Double Fisherman's (join two ropes)
Figure Eight, Bowline on a Bight 
Stopper Knot, Slippery Half Hitch, Timber Hitch