The Covid 19 pandemic has revealed the need to verify the existing principles of functioning of public authorities, in relation to various decision-making processes, both at the conceptual level and at law implementation. The action of the legislator and public administration towards the society and the economy is conducted using peculiar instruments to control the public administration system. These instruments are likely to be of a public or private law nature. This book takes a comparative approach to examine the issues related to digital transformation in the times of a pandemic regarding the use of public-law instruments in Poland and the wider European context. In particular, the research aims to identify what stage the development of digital solutions in the state's organization and its authorities has reached, including the organization of public administration; what the has pandemic changed. Exploring the concepts of digital transformation, pandemic and public-law instruments, it provides an analysis of European and national public-law instruments using digital solutions, security and cybersecurity during a pandemic, and concrete issues such as public administration, health protection and social security, economic activity and the system of public finances, and education during the pandemic is performed. Establishing whether particular solutions are durable and to what extent they create a certain standard of response to a threat, it makes recommendations for determining which of the existing solutions is useful for the functioning of the state and its organs and facilitates the performance of their tasks.