The storyline that's finally wrapping up in MGS4 has spanned six games and 20 years, so things have understandably gotten a little ... convoluted along the way. The series has seen some of the most oddly codenamed characters outside of G.I. Joe and more story twists than can be found crumpled up in M. Night Shyamalan's waste basket.

For those of you heading into MGS4 fresh - or have simply lost track of who's who and what's what along the way (we wouldn't blame you) - we present this painstakingly pruned primer to the names you need to know, with the hope that you embark on Solid Snake's final mission excited rather than bewildered.