What can be used instead of eggs or butter in a cookie recipe?

In many things you can use margarine, lard, or shortening instead of butter, or a combination of any of them. I actually use 1/3 butter, 1/3 shortening, and 1/3 lard for the fat in my homemade pie crust, which gives Excellent results. Just keep in mind that margarine has a higher water content than butter, so depending on what you are baking, the results may be just a little different than with butter.