Although recent research has demonstrated that public policy responds disproportionately to the preferences of affluent Americans, much less is known about the preferences of the truly wealthy – billionaires whose massive fortunes enable them to contribute millions of dollars to politics on an annual basis. Systematic knowledge of the preferences of this elite group is vitally important if we want to test the hypothesis that money tends to produce influence. Obtaining such knowledge has long proved challenging, however, because the ultra-wealthy are very difficult to study: their small numbers make it impossible to distill their preferences from even the largest existing public opinion surveys. And surveying them directly is impossible due to their very busy schedules and very private lives. This book addresses this problem using what can be called a web-scraping and public records approach, gathering and analyzing publicly available information about the wealthiest 100 Americans. It uses a novel, systematic online search process that identified nearly all public stances taken by these billionaires on an important economic and social issues over an approximately 10 year period. It also uses a comprehensive dataset of their financial contributions to political causes in order to examine their political actions, as well as several illuminating case studies to examine their behavior in greater depth. We find that these billionaires engage in stealth politics: they are exceptionally politically active, but strategically hide their political activities when their views differ from those of average citizens.