This course is one of a video series that documents common issues met in working with Microsoft EXCEL. Each part tends to present 10 cases that have been collected directly from a real working environment and are intended to share with professionals using EXCEL. For these cases to be relevant and organized, the course first provides a unique view of the Body of Knowledge (BOK) of EXCEL created by the instructor, which is a first in the EXCEL training and publications. The BOK illustrates the usual learning path of an EXCEL learner, naturally from basic to intermediate, and from advanced to expert levels. The BOK is open-ended with the top-level embracing all miscellaneous skills and future developments in EXCEL. Under the guidance of the BOK, all cases are tallied to the corresponding knowledge level so that our viewers may learn which areas they are good at and which require a bit more work. For each case, the course illustrates what the issues are, why the issues, and how to solve them. Also, the course encourages contributions from the audience who believes there may be better ways of resolving these issues. Those suggestions from the audience will be shared and acknowledged in the future part of the series. This course will serve as a refresher for all professionals who need to sharpen their EXCEL skills in their professions