Regardless if you need eggs for the salty or sweet kitchen - to bake or cook - eggs have several useful functions and features. 
Raising agent
When egg whites are whipped, they gain air. It is particularly useful for cooking gratin, mousses, meringues and roulades. The best results are achieved when the egg white is at room temperature. 
Binding agent
When the egg is heated, it has a good ability to bind the various ingredients together. An egg can bind twice as much liquid as its own volume. This quality is a plus for getting meatballs, meatloaf, pancakes and the like, to stick together.
Smoothing agent
The egg yolk’s ability to mix or smooth is useful when making e.g. ice cream, custard and sauce.
The egg yolk’s ability to emulsify is used mainly when making mayonnaise, bearnaise or hollandaise sauce. Just keep in mind that the sauce must not boil or it will separate, as the yolk becomes gritty at high temperatures.
Clarification agent
Egg whites can make a murky soup or fruit juice clear. Add a little egg white while heating up the mixture. The impurities in the soup or juice will bind themselves to the proteins, which can then be filtered out.
Colouring agent
Bread and pastries that are brushed with a lightly whipped egg before baking get a delicious glaze.