Book excerpt: This state-of-the-art book deals with advanced spatial modulation (ASM), which are a special class of recent Multiple-Input Multiple-Output MIMO techniques, for various applications like radio frequency (RF) based body area network (BAN) communication, free-space optical (FSO) communication, underwater optical wireless communication (UOWC) and hybrid FSO/RF communication. The performance analysis of such systems is achieved in terms of certain performance metrics and compared with other techniques available in the literature. Such SM based schemes can find its application in advanced 5G and 6G communications. The diagrams of the system models of the different schemes along with tables and examples will help readers get a clear understanding of this approach. This book elucidates required derivations, examples, and links various concepts related to this field so that readers can gain comprehensive knowledge. Pseudo codes or algorithms or MATLAB/MATHEMATICA programs are also provided so that readers can easily implement the concepts which they learn. This volume will be useful for students, researchers, and industry alike.