@turquoise-- Yep, contact cement works great, I've been using it for years.
Can you tell me what you will be gluing leather to? It actually makes a difference what the other material is. If you're gluing leather to leather, I recommend cement. Cement will also work for other materials like plastic, metal and wood. So you should be fine just getting this.
If you are going to be using other fabrics and if you're worried about discoloration, you might want to buy a "leather glue," also called "leather weld."