The following pages show some useful knots for use around the water (or anyplace you want to tie something up!).   Click on the picture of the knot you're interested in and it will take you to a scan of  the relevant page from "The Handbook of Sailing" by Bob Bond. 

Each knot has its special purpose and for each purpose a special knot (or maybe more).  Life is so much easier when a good knot is used!  If you're interested there are many good books out there on knots.  Learn a few, it can't hurt!