This booklet provides information to multiple stakeholders on the implementation of career clusters in Illinois. The booklet is an extension of the previous edition titled "An Introduction to Illinois CTE Programs of Study" (2008), and provides a resource for partners to understand Illinois' Career Cluster Model as its own adaptation of the States Career Cluster Framework. It is intended for individuals familiar with career clusters and programs of study and those beginning to learn about them. The booklet is divided into seven sections: (1) Perkins IV: main themes of the Carl D. Perkins Career and Technical Education Improvement Act of 2006; (2) Key Concepts: terms, definitions and benefits of the career cluster approach, to help partners become familiar with the States Career Cluster framework; (3) Career Cluster Framework: graphic representation of the essential knowledge and skills, the 5 career and technical education areas at the secondary level, the 16 career clusters, and the 79 career pathways; (4) Illinois' Career Cluster Model: visual example of the Health Science cluster and how different elements of the States Career Cluster Framework fit together in Illinois; (5) Implementation: information useful to preparing partners to implement programs of study, including the six guiding principles and partner roles in the process; (6) Acronyms: list for reference and ease of communication between multiple partners on programs, initiatives, and organizations; and (7) Resources: links to tools, research, and national organizations related to Perkins IV, career development, career clusters, and other information specific to Illinois. (Contains a list of resources and acronyms.)