If you have the money, you might want to pick up a Culinary Textbook. The New Professional Chef, the textbook for the Culinary Institute of America, or Professional Cooking, by Wayne Gisslen (the textbook I have and used in college), are both full of the why's and how's in cooking. They also have techniques on using knives, prepping veggies, etc. Both books are going to cost a pretty penny. I paid $60 for my textbook. You should be able to find either one at any good bookstore, like a Barnes & Noble, or other large bookstore. If you have a college with a Culinary program in your area, drop by the bookstore and see what they use for a textbook.
There are also some good cookbooks out there that give the "how's and why's" behind whatever you're cooking. Also, a lot of my cooking knowledge is experience. As you cook things, you tend to learn what's happening, and after awhile, you can basically think of what you need to do for any particular dish.
Peace, Love, and Vegetable Rights!
Eat Meat and Save the Plants!