pdfsam basic is a simple tool designed to split and merge pdf files.
Adobe Acrobat Plug-in, which performs imposition.
It automates the process of 3up, 4up, 6up, 8up, 10up or 12up a pdf document.
PDF Page Organizer Pro merges, composes, and re-arranges pages etc.
Imposition Wizard is an imposition software for Adobe Acrobat.
