PDFMerge is the sort of tool we've come to expect from Free PDF Solutions; a streamlined application that essentially makes it as easy as possible to do one job. In the case of PDFMerge, it's merging multiple PDFs into single documents. PDFMerge is based on the PDFSharp library. In addition to being free, PDFMerge's advantages are its small size (572.27KB) and speed. The latest version of PDFMerge, v1.19, has a new user interface. It supports Windows 98 to 8; we ran it on Windows 7.
Optional downloads are as common with freeware as commercials with broadcast TV, and PDFMerge is no exception, though with an emphasis on "optional." We declined the extras and opened PDFMerge's dialog-style graphical user interface, which has four buttons: "Add PDF File," "Remove Selected," and "Remove All," for adding files to the program's main window, and a "Merge Now" button next to the field for choosing a destination folder. All were easy to use, although we were surprised that we couldn't drag and drop files into PDFMerge. Up and Down arrows let us reposition documents within our queue. We started simple with a pair of multipage PDFs. PDFMerge finished the job so quickly we were unaware anything had happened, yet our target folder held the merged PDF, which opened and displayed normally in our default PDF viewer. Much larger batches took longer, of course, but the speed was still impressive, overall. While PDFMerge doesn't offer a Help file or any extras, its Web page includes some instructions and a support link.
If you need more settings or complexity, other PDF tools are available; some of them free, too. But within its scope, PDFMerge is a viable alternative to expensive, complex, all-in-one PDF programs if you just need to merge documents with ease.