I wanted an easy way to read the Handbook of Applied Cryptography ebook @ http://cacr.uwaterloo.ca/hac which is split into a number of separate PDFs, so I created PDFCat (PDF + "cat" from the *nix command). It uses CherryPy and PyPDF2 as well as Bootstrap for layout (because I wanted an excuse to try Bootstrap) and Sortable for the nice draggable, sortable list to change the order of the PDFs in the final document.