Most of the times when I had to split or merge a couple of PDF documents I had to use command line tools, which was kind of boring, since it isn’t a tool that I use often so what used to happend was that I always forgot the syntax usage.
Today was one of those times that I needed to merge two PDF documents so I’ve looked around and found PDF-Shuffler which is a small python-gtk application, which helps you to merge or split PDF documents and rotate, crop and rearrange their pages using an interactive and intuitive GUI. It is a frontend for python-pyPdf.