Baking is a way of cooking sweet or savory items in the dry heat of an oven. Although baking itself is a relatively easy process, it is good to have some knowledge of the role each ingredient plays in creating the final dish.
Different ingredients strengthen, bind, thicken, sweeten, leaven and add moisture. Some ingredients, like milk and sugar, perform multiple roles. And others will only carry out their duties under very specific conditions. For this reason baking is often compared to the science of chemistry.
You shouldn't be intimidated by baking though. A reasonable knowledge of basic methods and ingredient functions opens up a world of variety and creativity that is the raison de faire cuire au four of the typical pastry chef.