Since the late 1960’s the methodology to develop a system (SyS) has been documented and utilized with remarkable success. However, with the advent of more complex systems, such as, Federation of Systems (FoS) and System of Systems (SoS), the systems engineering (SE) community has diverge into three system perspectives, e.g., Sys, FoS and SoS. This divergence becomes complicated, costly and risky for each system developer, as specialized system development processes are required. In addition, the SE skill set becomes specialized by the system perspective and will result in a critical shortage of SE proficient in each system perspective. A solution to this dilemma is to evoke a core SE technical development methodology that is common among the SyS, FoS and SoS development effort and customizing their nuances in a modular form. In effect, creating a library of SE development processes that has a common core and enhanced for a SyS, FoS or SoS application. A SE practitioner is then equipped with processes that have commonality and their uniqueness identified for a specific SyS, FoS or SoS application. To fully understand the commonality and nuances of the SyS, FoS and SoS development efforts, four system development perspectives are required: System, Development, Process and Organizational. The System perspective establishes the boundary, definitions, assumptions, and importance of the development effort. The Development perspective establishes the classification of the development effort. The Process perspective establishes the core SE processes of the development effort. The Organizational perspective establishes the organizational structure for executing the effort. The nuances of the SyS, FoS, and SoS development efforts are identifiable from the System, Development and Organizational perspectives. While the focal point of commonality is with the System Process Perspective. An ideal abstract process pattern in the maturation technical development process models (TDPM) is identifiable within ANSI/EIA 632-2003, CMMI-DEV 1.2, and IEEE/ISO/IEC 15288-2008. The ideal abstract process pattern consists of the system process perspectives of Define, Solve, Realize and Evaluate. While the embryonic TDPM in IEEE STD 1220-2005 and MIL-STD-499C lack the full abstract process pattern. The ideal pattern can also be identified in seven elements within the SoS TDPM described in the DoD SE Guide for SoS. A four-step process is used to develop a library of SE development processes. Step one is to establish a taxonomy of all possible development efforts. Step two is to define a methodology that effectively develops each specific instance of the systems development effort (system taxa). Step three is to create a system development methodology for each system taxa based on knowledge gained through deduction. Step four is to continually improve the system development methodology with knowledge gained through experience. A library of SE development processes allows SyS, FoS, and SoS development to diverge properly from a common point by identifying the commonalities and differences between each development effort. The library also establishes a baseline for prescribing each technical development effort. System developers utilizing a library of SE development processes secures SE credentials and will establish themselves as a premier system developer.