This book presents new software testing technqiues designed for web application testing and security testing. These new software testing techniques are developed based on combinatorial testing techniques, to help software engineers to systematically detect the software defects with reasonable costs. This book detailedly discusses how to adapt general combinatorial testing techniques to web application testing and security testing fields. In addition to the software testing technique design, this book also explains how to automate the testing processes with three implemented prototype tools. Those protoype tools have been applied to open source applications, like Online Book Store web application and Gzip. The empirical stuies show that these new testing techniques are effective in detecting defects existing in the software implementation.