Most of the people rely on a full-screen editor to write code, a compiler to translate it, a source-level debugger to correct it, and a source-code control system to archive and share it. Three decades later, these are still the primary tools developers use to write software. Although they've been refined, the tools have neither progressed to meet the challenge of complex software nor evolved to exploit faster computers. Today, tools from an era of computational scarcity run on machines four orders of magnitude faster. Developers are struggling to write, understand, and manipulate large, complex software, while vast computational resources sit idle beneath their desks. Microsoft Research has developed two generations of tools, some of which Microsoft developers already use to find and correct bugs. These correctness tools help close the gap that separates a programmer's intent-which can often be concisely stated-from the vast amount of code required to realize that goal. A developer's job is to bridge this chasm; the job of correctness tools is to ensure that the resulting span is straight, level, and connects the right points. Errors in both categories are typically found through static program analysis, which explores possible program executions without actually executing the program