For thousands of years, mankind has both used bacteria and suffered from them without actually being aware of them, until 340 years ago when Anton van Leeuwenhoek observed bacteria for the first time. People then realized that they are surrounded by a wonderful and, at the same time frightening, micro-world. Only during the second half of the twentieth century did researchers begin to unravel secrets of bacterial cells, and today the amount of knowledge in the field is in an exponential growth stage. However, we are still far from an overall understanding of bacterial cell processes. This book is another step towards revealing principles and mechanisms of bacterial functioning and contains contemporary data and results in hot topics such as bacterial biofilm formation, multidrug transporter proteins, bacterial cells' adaptation to toxic compounds, bacterial gene regulation, cytotoxins and neurotoxins from Gram-negative and Gram-positive aerobic and anaerobic bacteria, bacterial sensitivity to photodynamic chemotherapy and kinetic analysis of bacterial growth. This book was written by researchers and lecturers from leading universities and research institutes in Europe, North America and Asia. It is addressed to the scientific community and may be interesting for researchers and students in the fields of microbiology, biochemistry, molecular biology, bioorganic chemistry and medicine.