This is not to do with the product, it is to do with the shipping. I ordered a physical version of this book and when I received it, I discovered that the spine of the book had been glued to with some form of adhesive tape. This caused the spine to become damaged when removing it from the box (which took several minutes of applying Goo Gone) so that parts of the spine now appear "bubbly" instead of smooth. I am not pleased with this for obvious reasons. If you are going to ship physical product in the "folder" style boxes instead of standard rectangular boxes, please take care not to adhere said product to the box.