PDF Maker Class is a very complete and professional library (specifically a .NET component) that lets you, via programming, generate PDFs from practically any type of file (Word documents, Excel sheets, Powerpoint presentations, MS Access reports, Cristal Reports, AutoCad drawings, text files, graphic images, etc).
From PDF Maker Class the programmer can even combine different documents together (for example a DOC with an XLS or with a graphic image) in the resulting PDF.
It is also possible, from PDF Maker Class, to establish the levels of encryption in the PDF, and also a password to access its content.