How to Make a custom map in Left 4 Dead

A map is a map is a map. Unless, of course, it's a map that you're using to navigate around Left 4 Dead. Having a customized map design lets you quickly find safety points, fellow players, and identify zombie locations so you don't, well, die.

The tutorial is excellent for those who are new to map design as well as for those who are experienced source mappers. Now check out this tutorial and get designing!