Outlook groupware without MS Exchange Server (shared PST) "Public OutLook" make it possible for several users to share an Outlook-PST file at the same time. The shared Outlook-PST files with full access and rights for read and write. To share contacts, calendars inboxes or tasks, are one of he most important functions of groupware solutions. The program Public OutLook supplies this alternative access with all Outlook versions 97-2003. Normally it is not possible without a MS Exchange server to use Microsoft Outlook together in a network to share these information's and functionality directly in MS Outlook with every rights. As base, Public OutLook use here a common Outlook data file (PST). This programs share not only contacts or dates, it shares the hole Outlook PST file. Whether it concerns now contacts, dates, functions or post office inbox, a central enterprise further accesses to an Outlook structure is possible with this program. All co-workers can use the same contacts. Each co-workers can see who has which date or who is busy with which task. They have all functionalities on this central Outlook as in a personal Outlook file. Write rights, reader-genuine or rules assistant. All built-in functions are preserved also in the Public Folder. The existing Outlook network does not have to be modified. With "Public OutLook" a network can be implemented with all Outlook versions. "Public OutLook" is not a synchronisation program, it is a "Store Provider" like MS Exchange Server. Also for Lotus Notes or Novell GroupWise users, who would like to change to Outlook, is this an interesting solution. An offline notebook synchronisation is still developed.