Most bacterial and fungal microorganisms have the ability to adhere to a biotic or abiotic surface and initiate biofilms. Biofilms are dynamic entities of microbial cells embedded in a self-produced polymeric matrix, which protects them and promotes their development on biotic and abiotic surfaces.The knowledge of its physical and biological characteristics appears to be crucial. This task requires numerous techniques to measure, quantify, characterize and observe these microbial biofilms.This book is a gateway to this cooperative way of life, very different from the planktonic state we know.