This document supports understanding, adoption and use of prEN 17748-1 (ICT BoK) that provides a reference of 42 knowledge units as required and applied in the Information and Communication Technology (ICT) professional work environment that can be understood across Europe. This document supports Information and Communication Technology (ICT) stakeholders dealing with ICT Professional knowledge, skills and competences from multiple perspectives, in particular: educational institutions, learning programmes and certification providers of all types including: Vocational and Educational Training (VET); Higher education (HE); Continuous Professional Development (CPD); ICT service, user and supply organizations; ICT professionals, managers and human resource (HR) departments; social partners (trade unions and employer associations), professional associations, accreditation, validation and assessment bodies; market analysts and policy makers; and other organizations and stakeholders in public and private sectors across Europe to adopt, apply and use the Foundational Body of Knowledge in their environment as one fundamental building block of ICT Professionalism for Europe. See Figure 1 for illustration of document scope and target groups. A close connection with EN 16234-1 (e-CF) and CWA 16458 (ICT Profiles) are a design element of prEN 17748-1 (ICT BoK). This application support document details how to approach the complementary application of each structure by varied stakeholders of the European ICT Professionalism eco-system. It supports the use of a shared neutral reference for ICT professional development. This interconnected application is illustrated in Figure 2. Nevertheless, the ICT BoK can also be used as a stand-alone tool.