It's pretty clear that PDF files are the new "must use" when it comes to document handling. Who doesn't use a PDF nowadays? They are smaller than other similar files, can be viewed on Windows, Linux and MAC, and anyone can protect their PDF files with encryption and password. Because of the wide variety of free conversion tools available today, everybody can convert whatever files they want to PDF.

Students use a large variety of operating systems on their computers. Teachers can make sure that their courses will be viewed properly by converting them to PDF files. Universal deployment is maybe the most important asset of PDF format.

Companies and business users can keep their internal documents as PDF files, benefiting from their smaller size and making sure those files are read only by employees who know the password. PDF security is another important feature that made the PDF format so popular.

Finally, home users are using PDF files because Adobe did a very smart thing: Adobe Acrobat Reader is used only for viewing PDF files and is free. This way they made sure PDF format is available for everybody.

After PDF files became widely used, some new needs appeared. Users wanted to extract only a couple of pages from a PDF files. This could be done only by using dedicated software: a PDF splitter tool. Also, somebody at one point wanted to combine two or more PDF documents into a single file. They needed a PDF merger tool. Adobe made those tools, but they were not free. And because of their branding and marketing costs, those tools were pretty expensive.

Luckily, free tools emerged during time, but they were not developed by Adobe. Third party publishers made them available to public use, trying to gain a market share.

PDF Sam is the most popular tool that can be used to merge and combine PDF files. Originally started on the Source Forge platform, it is developed in Java and comes in two editions: a free one, and for those who donate any amount, an enhanced edition. It offers the basic PDF split and PDF merge operation, and in the enhanced version, file encryption.

Adolix Split and Merge PDF is quite a young entry in this market. Adolix developed this tool in Visual Basic, and focused on the graphical user interface. Their aim was to make it as user-friendly as posible. Following PDF Sam steps, Adolix's tool was first available as a free edition. Users could split and merge PDF files with just a few mouse clicks. At some point they also offered a Professional edition. Users could merge more than 5 files at once and split large documents into PDF files with the PRO version.

Other vendors also released tools to handle the split and merge PDF process. Adult PDF, Very PDF, AcroPDF and NitroPDF are only a few of the companies that entered the market with free or paid versions of those type of tools.