This book grew out of my desire to understand the mechanism of silver nanoparticles and comparison of antimicrobial activity of various sizes and shape of nanoparticles synthesized from aqueous and non aqueous method.As utilization of silver nanoparticles is continuously expanding, the risks regarding the health implications due to lack of information on the basic toxicity of size and shape dependence of silver nanoparticles are enormous. Therefore, one of the objectives of this book is to understand the acute toxicity effects associated with various sizes and shape of silver nanoparticles. While this book is intended to be read cover to cover, it can also use as a reference work. We are in the midst of the veritable explosion in nanomaterial are at the heart of it. I hope you put this book down as excited about the field as I have been in the writing of it.