OK, the basics of knife sharpening are easy enough. When a knife has been dulled, you have a couple of options. If you have a very finely-figured edge, you may be able to re-align the edge by honing it on a steel. This is the preferred method of "sharpening" chef's knives and butcher's knives when you need only light maintenance to keep the performance tip-top. If the edge is very worn and/or won't hold a decent edge after being honed on a steel, you need to actually re-shape the edge. I recommend that you you buy a decent 6" diamond-impregnated stone (or two, maybe fine and very fine) and re-shape your edges with these stones lubricated with clean water to clear away abraded material, and keep the edge cool. If you have spent $70-80 on a hand-forged French chef's knife, the last thing you want to do is ruin that edge.
Don't worry so much about metallurgy - let the knife-makers take care of that. Your primary concern is taking care of your knives properly and not un-doing all the good work that you paid for. BTW, if you have ever seen Alton Brown's show on knife-sharpening, please disregard it at all costs. Letting some itinerant sharpener with a van draw sparks off the edges of your prized knives with belt-sanders is beyond ignorant. Brown is clueless, and his production team really screwed up this one.