This manual, Drones A Report on the Use of Drones by Public Safety Agencies - and a Wake-Up Call about the Threat of Malicious Drone Attacks 2020, is about two opposite but related issues: (1) the use of drones by police agencies to protect public safety and (2) the use of drones by malicious actors to commit various crimes such as acts of terrorism. Thus, the story of drones is about two radically different sides of the same coin. This report should be seen as two separate reports. The bulk of the document, chapters 1 and 2, provides guidance to police and sheriffs' departments about how to identify the ways in which drones could facilitate their work and how to create a drone program to accomplish those goals. The remainder of the document, chapter 3, is about the malicious use of drones. As of early 2020, the United States is extremely vulnerable to drone attacks because only in late 2018 were federal law enforcement agencies given the legal authority to use the most effective types of technologies to detect and mitigate drone threats. Local police and sheriffs' departments still are unable to purchase or use most counter-drone technologies because of concerns they might break the law when employing them and the danger of interference with air traffic in the National Airspace System. This is not merely oversight by Congress and federal agencies; there are important reasons for limiting drone detection and mitigation technologies. Careless or unskilled use of these technologies could result in disaster. For example, technologies that use radio signals to jam an incoming malicious drone or seize control of it, improperly used, might interfere with radio signals used by commercial or private airplanes or air traffic controllers. A number of federal and local law enforcement agencies have begun to explore counter-drone strategies at major events and mass gatherings such as the Super Bowl. But this work is still developing. Federal, state, and local lawmakers and government officials, including law enforcement officials, should accelerate their efforts to address these issues as soon as possible. The drone strikes against oil facilities in Saudi Arabia in September 2019, which temporarily disrupted approximately half of that kingdom's oil production capacity, demonstrate how much harm can be done by the malicious use of drones. The United States must not wait until it suffers a drone attack to undertake large-scale efforts to develop strategies by law enforcement agencies at all levels of government for (1) identifying drone threats and (2) mitigating drone threats in real time.