The importance of care when tying knots is not to be overlooked. Even climbing legends, such as Lynn Hill, have mistakenly disregarded the quality of their knots, with near-catastrophic consequences:

Basically, I didn’t tie a knot. I put the rope through my harness, but didn’t finish tying my knot … I leaned back to abseil back to the ground and just kept falling.

As always: climb smart.

Rewoven figure 8 knot

This is the knot for tying oneself into the rope. Although other options are available, the rewoven figure 8 is the first to master.

Stopper knot

Sometimes called a barrel knot, adding this to a rappel closes the system, and it ensures that the rappeller won’t lower off the end of the rope. Additionally, this should be added to the open (non-climbing) end of the rope when belaying another climber. Play it safe, and develop the habit of always throwing these in.

Bowline (and double bowline) knot

The bowline can be used in various anchor-building scenarios, and some climbers use the double bowline as an alternative to tying into the rope. This knot is highly not  recommended for new climbers tying in. While it has the advantage of not tightening up after a big fall, it serves two key disadvantages:

1) it’s more difficult to correctly tie; and

2) it’s more difficult for the climber and belayer to inspect.

If choosing to tie in with a double bowline, we recommend seeking instruction from an expert or AMGA-certified guide.
Provided is Mike Barter’s humorous take on the bowline. Although strong, its applications are best suited for uses other than tying in:

Related: Climbing Anchors: Basic Principles

Figure 8 on a bite knot

Serves a variety of purposes, but is often used in anchoring scenarios as an alternative to the clove hitch.

Butterfly knot

The butterfly knot is often used to tie into the middle of the rope. A a pull from any orientation (sides or middle loop) will not cause the knot to become undone.

Related: Learn about hitches and bends.