I'm really not joking when I say this book held a strange fascination for me. There was something oddly authoritative about this being the actual regimen for a military service with the word "Royal" right there in its name. It claimed to be all you needed to achieve fitness, and as a chubby little nerd I believed it. I've always been a sucker for claims of expertise as well as for things that are short. Because I am gullible and I am lazy. But I was not alone in my interest in the program; 5BX was a big hit in the 1960s and the promotion of regular, intensive calisthenics paved the way for the aerobic craze of the 1970s.
Looking at the book today (I found a PDF of the 5BX pamphlet which was originally published on its own) what I'm most captivated by are not the exercises—a series of standards, some of which are neither effective nor safe—but the lengthy introduction which makes the case for physical fitness. Of the original 32 pages only 10 actually described the exercises; the rest were a series of cartoons, charts, and pep-talk to convince the sluggard to adopt this life-changing process.