Although we are in a constant war to get rid of them, we have always lived in a world dominated by microbes. Interestingly, there is a new science field that aims to reveal the secrets of the microbial planet, but not as a tactic of war. Even though we donít pay a lot of attention to our microscopic friends, the microbial communities support all life of Earth, even ours. For this cause, understanding the characteristics of this unexplored microbial world may help us to solve many of the environmental, medical, biotechnological, energetical, and economical challenges of the world. The name of this new science is Metagenomics.