The difference between these three types of wallpaper is the method of applying or activating the paste before hanging the paper. When using Paste-the-Wall wallpaper, the paste is applied directly to the wall before hanging each strip. This wallpaper is made with a special backing that does not expand when wet; therefore, it does not need to soak as in other application methods. When using the Paste-the-Paper method, the paste is applied to the back of the wallpaper before hanging. This method requires a process called “booking” which is a way to activate the paste while letting the paper rest before hanging the strip. Pre-pasted paper already has adhesive on the backside of the paper which is activated by dipping the wallpaper into a tray of water. The paper also requires the “booking” process after the paper has been soaked in water.