It is the ability for more than one user to have access to a document (actually, any type of electronic file) from the location where it is stored on the network. We take this for granted in a Local Area Network (LAN) environment, but when we start looking at users scattered among multiple remote locations, or perhaps clients, professional associates, and others, it gets a lot more complicated. Suddenly a host of important security concerns begins to come into play. You obviously don’t want just anyone to have access to your network, and allowing “selective” access requires the specialized skills of a trained network administrator.