If that doesn't work, or if that website goes away sometime in the future, you can also download the PDF from my website here (6.3 MB).
Also, I've turned it into a Blurb book. The link to order the book is here.
The book design is very simple, but it's intended for my 4-year old son :-) I ended up using 39 different photos, and there are 18 subject pairs for him to guess. Some are pretty simple, but some will take some thought. Of course his second reading of the book will be no challenge at all. His mind is sharp and he remembers everything. He even tells me when I've accidentally skipped a page while reading him one of his other books.
For me, this wasn't really about producing a book. The process of shooting and editing was good practice. This has been a nice photo project and has given me experience in doing the photography work and making a final presentation from it.
Hopefully Henry will enjoy it. I would guess that this book will become well worn within just a few months and we'll probably have to order a new copy for Michael when he gets around to enjoying such a book.