A book from someone who explains how to perform the exercise, nothing more. From an author I am not associated with. There are probably a zillion videos about

A book from someone who explains how to perform the exercise, nothing more. From an author I am not associated with. There are probably a zillion videos about 5T on youtube, if you prefer and the original text (1930 or somesuch) is probably available for free as a pdf. I believe most people would prefer something more "modern", though, that's why that specific book is on the page. (Yeah, I have a referral link to Amazon on the left, but I am not exactly forcing anyone to buy the book).