Overview Well-testing papers under review for this feature become more numerous and varied each year. Consequently, this issue's papers represent a cross section of only some of the varied resource-development conditions under which industry professionals are designing and evaluating wells to determine productivity and reservoir parameters. The analysis of pressure data with accurate rate information is the root of petroleum engineering calculations. Whether your need for measurement accuracy and resolution is a fraction of a psi for interference testing or hundreds of psi for qualitative depletion information on an infill-drilling project, knowledge of pressure is still fundamental. The first paper describes the approach one operator is pursuing to refine their knowledge of one of the largest tight gas resources in the USA. Described are the constraints, challenges, and ultimate solutions they developed in pursuit of optimizing the recovery of this significant resource. The second paper provides a good example how integrating well-test design and analysis with existing geologic- and reservoir-description information enhances the accuracy of the final results. The third paper provides insight into the detailed planning and preparation that go into a successful well test and shares the post-job analysis comparing the actual test results with the original objectives. I am always amazed at the considerable planning and expense that go into oil/gas recommendations and operations that still lack any priority for capturing important (and relatively inexpensive) results for reference and optimization. This paper is a good read for anyone wanting an appreciation of the issues to be considered for well testing in challenging environments. Many more good papers were reviewed than could be mentioned in this feature. The three selections listed for additional reading give us insight into the challenges faced and solutions implemented by service companies and operators to solve testing and interpretation needs in areas such as pressure testing while drilling, non-Darcy-flow modeling, and fracture properties of naturally fractured reservoirs. The SPE eLibrary is a valuable resource that I encourage all to search for additional papers in your area of interest within the far-reaching topic of well testing. Well Testing additional reading available at the SPE eLibrary: www.spe.org SPE 103803 "Formation-Pressure Testing While Drilling in Bohai Bay's Challenging Environment" by Ulrich Hahne, SPE, Baker Hughes Inteq, et al. SPE 107853 "Modeling Non-Darcy Flow and Perforation Convergence for Vertically Fractured Wells" by H. Huang, SPE, Georgia Institute of Technology, et al. SPE 107418 "Effects of Stress on Fracture Properties of Naturally Fractured Reservoirs" by Abel Chacon, SPE, BP plc, et al.