The book is aimed at narrowing the gap between industrial aspects of mud engineering and its academic basics. It also sums up the experience of handling unconventional and unforeseen problems related to well-bore instability with the right composition of mud to facilitate correct properties in drilling fluid design, and thus minimize/eliminate non-productive time. If the book is able to fulfill any / all of these objectives, then the purpose of writing the book is served. It aims to reach out to petroleum engineering students and those mud engineers who have just begun their career in the oil field, with many questions wandering in their minds, and aims to answer them in a manner that makes sense to their limited exposure with the least technical jargon, but effectively quench their thirst of inquisitiveness. For the professionals who aspire to climb the ladders of success to reach the corporate jungle, the book cautions them that what appears costly superficially need not be always costly and thus spend enough money to have a right team of professionals surrounding them and not the guys who will always agree to them for the fear of loss of their job.