This consolidated portfolio examines the critical role of application systems in project, program, and portfolio management. It delves into the relevance of system thinking, systems engineering, and the selection of appropriate PM applications to meet internal and external project objectives. The portfolio explores how these systems contribute to effective knowledge management, decision-making, performance monitoring, and change management throughout the project lifecycle. It also analyzes the advantages and disadvantages of manual and electronic systems, highlighting contemporary developments in PM application systems.