another legitimate scientific journal, be prepared to serve as a reviewer too (Fig. 1), especially if you are the designated corresponding author of your published paper.Avoidance of stimuli or situations that are perceived threatening is a characteristic of adaptive fear (Krypotos et al. 2015). If you have never reviewed before, do not worry about your ability and performance. The editor probably knows that the chances you have reviewed before are extremely low. I bet he/she does not depend solely on your review report, but in any case you can always clarify to the editor that this is your first experience. Yes, you can input confidential comments that only editors will see. Bear in mind that an editor may also want to train you. Proficient and highly proactive editors often invest time to expanding their reviewer pool, thus an editor may want to give you a chance to experience reviewing; you may be invited in addition to an existing minimum number of experienced reviewers. Hence, do not fear to accept an invitation to review.Reviewers are sentinels of science (Fig. 2), and the success and progress of science depends on the reviewers' diligent work. Editors' decisions largely depend upon reviewers' recommendations, and can finally impact the directions in specific research areas, and, thus, the progress of scientific advance, accumulation of scientific knowledge, and societal development. Hence, peer review, including reviewer's roles and responsibilities, is a widely discussed subject in the published literature (suggestions for further reading: