This course discusses metrology of pattern placement (registration, alignment, and overlay) in IC manufacture. Starting with the definitions of pattern width and placement in design and in patterned materials, this course presents a rigorous approach to dimensional metrology. Going from registration to alignment, then to overlay, it gradually introduces and reviews the key technologies, common applications practices and technology-limiting issues, ultimately deep-diving into optical image- and diffraction-based, and SEM-based overlay metrology. Graphic accounts of metrology-process interactions and key technology learning lead to analysis and discussion, drilling into specific technical details and general methods. Attendees quickly begin to notice applications and technology gaps and to propose solutions, gaining vicarious familiarity with this field, practical understanding of how things work, and of the many factors involved, expanding their outlook. Not required to run a metrology tool in production, this is a prerequisite for successful troubleshooting, engineering change, and development. This course is about foundations of Overlay Applications Track and is intended for attendees interested in anything to do with overlay.