[header] How to create invisible shelves [title] Choose a suitable book that you won't want to read ever again. [step] This will become the " sacrificial " book that makes the shelf. Since it will be supporting other books, a large, hardcover book works best. 
[title] Trace an l-bracket onto the inside of the book. [substeps] Open the sacrificial book's back cover and use your tape measure to find the halfway point.