My wife has owned a copy of this book for a many years, and since getting married we have proudly kept in the dowstairs loo as a source of 'light relief'. I myself have only really started paying it attention for a short while.
It is clear that the only 'wink' in its covers is a hooded one. The author has marvelously made up names of persons of little renown and passed them off as the originators of such well known words as doldrums, coffin, and of course, gusset.
A great gift to buy for show-offs of the intellectual persuasion. Send them a copy and see how long it takes them to get the joke. It's took my wife 10 years - what a hoot!