Whenever you buy a commerically made book, you never question if the book is going to retain it's form when you add your photos and other memorabilia.
However, an important factor to know when ordering a book from a craftsman who creates handmade books is how they create their binding.
I, like many other book binders, cut small slivers of card stock and place between the pages in the bindings of my books. These small slivers of card stock are called "spacers".
Spacers build up the binded edge of your book. When you first buy a handcrafted book, you might noticed the binded end of the book is thicker than the outer edge of your book. This is because those spacers are the same thickness as a photograph. Until you place your photographs inside your pages one side will be slightly wider then the other. But, once you place those pictures inside the pages, the good thing is that your book will remain it's proportioned size.
Really, it means you won't have a book that looks like a triangle from the top when your done. I'm sure you've seen those kinds of books before. The pages become thicker than the binding and doesn't hold the books shape so it feathers out at the end.
So that my friends, is why you'll find spacers in all my albums and guest books.