A hack is any means of subverting a system's rules in unintended ways. The tax code isn't computer code, but a series of complex formulas. It has vulnerabilities; we call them "loopholes." We call exploits "tax avoidance strategies." And there is an entire industry of "black hat" hackers intent on finding exploitable loopholes in the tax code. We call them accountants and tax attorneys. In A Hacker's Mind, Bruce Schneier takes hacking out...