From publisher blurb:
In the D&D Gamma World game, you get bonuses on skills based on your primary and secondary origin, and also a +4 bonus to one randomly rolled skill that represents what your character is good at doing.
However, this is just a straight 1d10 roll that doesn't add any actual flavor to your character. You could make something up “that +4 bonus to Science – is because I'm a … scientist, yeah, that's it” but the rules as written don't – give you much to work with.
This document is designed to expand on the skill system in the D&D Gamma World rulebook by letting you roll a profession for your character. This is an optional system, and it may be superceded by Legion of Gold when that supplement comes out.