Many people only wonder what they can do to boost their immune system after they are down with fever, cold and our worst nightmare, cancer. Our immune system is amazingly complex. It is a network of cells, tissues and organs that work together to defend the host against attacks by foreign invaders. Having a little knowledge about the immune system will stimulate your interest into taking care of your own well-being in the long term. I will keep it short and interesting, so read on!