Information Systems are viewed as a set of services creating a workflow of information directed to specific groups and members. This allows individuals to share ideas and their talents with other members. In such manner, tasks can be carried out both efficiently and effectively. Due to the nature of Information Systems that revolves around creating information useful to users, and in some higher forms of Information Systems creating knowledge, management of information and/or knowledge is part of their functionalities. In this paper we aim to study the placement of Information Systems as part of a System of Systems (SoS), as these large systems poses significant technical improvement in terms of information interoperability that overcomes conceptual and technical barriers. Therefore, we move towards defining and modeling System of Information Systems (SoIS). This paper discovers what is currently known about Information Systems and Systems of Systems, and proceeds towards suggesting an architecture of a System of Information Systems that integrates several Information Systems and allows information to be transferred at ease between those different components.