From the Introduction:

Remember that the average act, which can be acquired by anyone without much practice, is seen on the Halls so often that one becomes absolutely bored with it. They are known in the profession as "Penny a bunch Acts." Now with a little application, you can stand apart from this bunch, and be a specialist, so this book is offered in the sincere hope that you will be able to glean an act from it, and we tell you to do so in all confidence, as the material is original, and has seldom, if ever, been used in public.