Lex Scientia Law Review Volume 5 Number 1, May 2021 raised the main topic of "Legal Certainty and Challenges of Legal Protection Guarantee in Indonesia". This topic is very relevant to the current condition of Indonesia, where many justice and public protection guarantees have yet to be fulfilled. This condition is certainly one of the challenges in the field of law and several other sectors that influence each other. Legal certainty and fulfillment of protection are constitutional rights of everyone that the state has guaranteed in fulfilling them. The law itself is issued as a guarantee of protection for people who need legal certainty and legal protection to protect and fulfill their rights. This edition consists of several writings and book reviews containing a number of current thoughts on problems in legal certainty and guarantees of current legal protection. Later, it aims to find a balance between legal certainty and protection guarantees needed by the public, which the state must fulfill. This edition also specifically presents thematic topics so that the Lex Scientia Law Review can be explicitly read and helps various research related to law and its development. The authors of this edition consist of several institutions, both domestic and foreign, namely: Multimedia University Melaka Campus Malaysia, Cabinet Secretariat of the Republic of Indonesia, Gadjah Mada University, Udayana University, Tarumanagara University, State University of Semarang, University of Mataram, and University of Muhammadiyah Malang.