This book covers most of the contents found in the university and other tartiary institutions syllabus. It also provide a step by step understanding to the challenges encountered in the process of variation and valuation in contract estimation and it's management. This book is therefore recommended for lecturers and students as an essential instructional text book for teaching, training and learning in Variation and valuation in contract estimation and Quantity Surveying courses. Additionally, it serves as an imperative manual for all professionals in built-environment as it enhances effectiveness and efficiency in project evaluation and successful delivery.