PDFtk - The PDF Toolkit 2.02
A friendly graphical tool for quickly merging and splitting PDF documents and pages.
PDF Labs software
DlSoftware247 lists 2 Windows programs by PDF Labs, mostly Document Management software. The most popular are PDFtk - The PDF Toolkit, PDFtk Server.
PDFtk Server 2.02
A command-line tool for working with PDFs, commonly used for client-side scripting or server-side processing of PDFs.