This book is novel in that it provides insights into the effects of information provision on people's perceptions and behavioral changes during the pandemic, and provides empirical evidence on its mechanisms and policy implications from different perspectives. It compares the different characteristics and effectiveness of information sources from the government, the news media, professionals in the field (health care workers), non-professional ordinary people, and the close environment, including family, friends, and colleagues. The consumer externality is the key concept in the analyses, as it identifies the effects of one's own consumption on the actions of others in constrained situations such as pandemics. Data from surveys conducted in Japan, the United States, and Germany suggest some implications for policymaking during a pandemic. One is related to differences in the characteristics of information. For example, information from experts in the field is perceived differently than information from other sources. Similarly, information from authorized organizations such as government and the news media remains critical in an emergency. Another relates to behavioral changes caused by the provision of information. Clearly, the effects of information on behavior change depend on the characteristics of the activity being addressed. We examine the effects on out-of-home and in-home activities during the pandemic, both of which focus on leisure activities, and show that the effects of information on each activity are quite different. Overall, this book provides empirical evidence for the importance of information dissemination policies that work with appropriate information providers and take into account country-specific attitudes to information.