Just two leader knots? Yes, there're are plenty more but two is all you need - one for joining lines of different materials and diameters, and another for similar line types and diameters.
There are two basic types of leader - one is a strong shock leader, required to withstand the high shock loads of casting, and the other is a hard-wearing leader required to resist abrasion or the teeth of predatory fish.
Safe, reliable connections for these various scenarios are described here.
First, double back the end of the single strand wire leader and thread the mono through the eye produced.
Next, start whipping back the mono over itself and the leader.
Then, make about ten turns before tucking the tag end of the mono through the loop such that it emerges on the same side as it entered.
Finally, lubricate with saliva before smoothly pulling the knot up tight.
Trim both ends, and that's it - a knot for connecting different line types and diameters
First, lay the two lines to be connected alongside and form a loop as shown here.
Now make at least four turns (more for light lines) around both strands and through the loop. Wet the knot with saliva and start tightening it by first pulling on the tag end in the direction of the arrow.
Then, with the knot now well consolidated, snip the ends off close and pull on the two lines to slide the two knots towards each other.
And that's it, the finished knot for joining a nylon monofilament main line to a fluorocarbon leader.
Artwork by Andrew Simpson
If you like the idea of having the most popular sea fishing knots all together in one place for easy reference, this handy little pocket guide is just the thing.
It sets out in step-by-step instructions and nicely drawn sketches how to tie all the knots you'll ever be likely to need, including another leader knot - the Shocker Knot.
Being spiral bound it opens flat, leaving both hands free to tie the knot - and it's waterproof!