Merge, convert, split PDF documents, even encrypt or extract PDF parts, with PDFBox
PDFBox is a java app that will let you handle PDFs by just taking advantage of Windows Command Prompt. Of course you need to have Java installed.
With PDFBox you can create PDF documents, read, convert, print, encrypt, decrypt, extract content (texts and images).
The program lets you also convert plain text files to PDF, and merge multiple PDFs or split a PDF.
A very powerful, although free, program you may like to try if you work frequently with PDFs.