The bowline can be tied quickly and is easy to adjust. It is also very easy to untie, so the tail should always be secured with a backup knot (e.g., an overhand knot). The bowline can be a little difficult for novices to learn, but it is easy to remember with a little practice.
This illustration shows how to tie a bowline. The trickiest step is to get the correct strand of the loop on the bottom (step #1 in this illustration) so it will get captured (step #4). (You can click on this illustration to enlarge it.)
Some people learn to tie a bowline using the memory aid, "The rabbit comes out of its hole, goes around the tree, and goes back down its hole." If that works for you, use it!
The "critical point test" (aka "scissors test") requires that if any one item fails, nobody should be injured.
A "bend" is a knot that joins two ropes.
A "hitch" is a type of knot that must be tied around another object.
The "whistle test" requires that if all rescuers let go, nobody should be injured.