Client/Server provides another level of sophistication in the implementation of systems. The concept of Client/Server is based on distributed processing, where programs and data are placed in the most efficient places. Client/server systems are typically installed on Local Area Networks (LANs) or Wide Area Networks (WANs). LANs can be defined as multiple computers linked together to share processing and data. WANs are linked LANs. For purposes of this book, we will restrict our discussion about Client/Server within the concepts of application development moving to cloud and mobile environments.