Freedom of speech, protected by our Constitution, has long been a vital component of political, social, and intellectual life in our country. The American Council of Trustees and Alumni (ACTA) has dedicated itself for more than 23 years to working with trustees to ensure that our nation's colleges and universities preserve this essential freedom on campus. This freedom is under attack on a disturbingly large number of our nation's campuses. The "heckler's veto," by which loud and sometimes violent protests prevent a speaker from delivering a lecture or participating on a panel, is one particularly obnoxious form of silencing free speech. Equally damaging and dangerous are the campaigns to discourage an invited speaker from coming to campus or to coerce a "disinvitation" of the invited guest. By understanding how and why these disruptions happen, as well as recognizing their potential to occur on virtually any campus, boards of trustees can develop policies to mitigate the risk of incidents that could readily bring physical damage and very negative public attention to their institutions. ACTA has long emphasized how essential boards of trustees are in establishing the principles and upholding the laws protecting free speech and free assembly at colleges and universities. Three primary aims of this guide are: (1) To educate trustees about the legal and ethical norms that make the practices of the "heckler's veto" and disinvitations inherently problematic; (2) To prompt self-scrutiny and preparedness by outlining key questions boards of trustees and others should be asking; and (3) To offer practical and clear guidelines to help trustees cultivate a campus climate where free speech can flourish.