Since developing the first discovered reservoirs in the United States with sucker rod pumps to the modern deep-water oil production in frozen arctic areas, we concern the improvement of hydrocarbon recovery. Improved Hydrocarbon Recovery is not a new concept while it is studied in the present book through a new point of view. Instead of classic presentation of different methods and treatments useful for improvement of oil and gas recovery, practical aspects of these approaches are discussed through numerous case studies provided in the book. In fact, there are many simple and effective methods to increase the recovery of crude oil with low capital costs and short payback period. As a rule of thumb, higher first stage recovery leads to higher recovery factor in the secondary and tertiary phases of production. So, early implementation of IOR methods and new production technologies will considerably boost the ultimate recovery of the reservoir.