“It's like writing two books at once, only harder,” Jim said to me when he asked me to take on writing this Common Book of Knowledge book while I was still writing the SSCP Study Guide. More like taking one subject, turning it sideways, and shaking hard, perhaps! Unlike the Study Guide, writing this book felt more like writing several hundred short white papers on closely related subjects.

Since this book needed to speak to troubleshooters, I drew on decades of teaching I'd received from many professionals in the military, in government, and in the private sector about the fine art and brute-force cybernetics of debugging networks, systems, highly secure communications systems, and all of the arcana of controlling space-based systems working many different missions. I've also drawn on years of working with small and medium but otherwise rather down-to-earth business IT systems and what it took to get them back into operations. Where that problem-solving focus comes through clearly and helps you shoot the troubles you have to deal with, I owe a great debt of thanks to those who let me learn how in real time.

Without the tireless support of the editorial team at Wiley/Sybex—Jim Minatel and Kelly Talbot—I think I'd still be struggling with unflowing the lessons and reflowing them into reference and troubleshooting memory-joggers. And as with producing the Study Guide, the technical review by Jacob Penovich, as well as by Tara Zeiler and Charles Gaughf at (ISC)², have all helped make what you have in your hands right now deliver the right content in the best way possible. Christine O'Connor, Kim Wimpsett and the rest of her team of proofreaders and copyeditors made it all look great too! Any remaining mistakes, omissions, or confusing passages that remain are mine, not theirs; let me know please when you find one!

Finally, I wish to thank my wife Nancy. She saved my life and brought me peace. Her strength inspired me to say “yes” one more time when Jim called me, again, about doing this book, and she has kept both of us healthy and happy throughout. We go together, on adventures like writing, and on ones for which we do need to pack a pocket handkerchief.