Abstract: Electronic warfare (EW) is commonly, and often deliberately, shrouded in complexity and secrecy. It is therefore probably not surprising that there are few top-level, comprehensible descriptions of the field that are accessible to the uninitiated. EW 101: A First Course in Electronic Warfare is one of the few books available that is targeted at non-experts and is intended to be easy to read without glossing over important technical details. The book is based on Dave Adamy's popular series of articles published in the Journal of Electronic Defense (JED) since October 1994 (for those interested in traceability, Appendix A maps the JED articles into the book chapters). Dave holds BSEE and MSEE degrees in communication theory and is very active in EW-related fields having been an EW professional in and out of uniform for almost 40 years. In addition to the EW 101 columns, he has published seven books. He provides EW-related courses around the world and is a regular consultant to defence and defence industry.