Days 36 and 37 of the 100 Days plan are among the most didactic but most fun: they instruct readers in how to structure and create a good sales letter. Rather than isolating the methods of sales copy as standalone techniques, I’ve included a short writing course that reminds and instructs readers in the core principles of written English.

Sources? Of course the usual suspects were on my desk at the time–Stephen King’s “On Writing” and William Zinnsser’s “On Writing Well“–so the methods aren’t anything most people will argue with. What’s interesting is just how often the very best sales letters (I studied over 1,000 for this book) agree with what makes readable prose, too.

There’s good copywriting, and there’s good writing. And the two aren’t that different.