A prominent high scale (fractions of a nanometer) measurement technique for material science - Atomic Force Microscopy (AFM), was introduced in 1980s but is now fast gaining significance in the field of biology. This technique is used to examine the topological surface of biological nanoparticles i.e. proteins, viruses etc. In addition, it demonstrates the physical attributes such as Young's modulus, bond strength, surface friction etc. of these nano-organisms. AFM is functional within physiologically suitable conditions i.e. liquids. This is the main reason of its significance in the realm of biology. The book presents an introduction about Atomic Force Microscopy along with the techniques and practices of sample preparations. It also familiarizes readers with recent research works on nanoparticles, proteins, viruses and living cells and their characterization.