Book excerpt: Following the formulation of the central dogma of molecular biology and the later discovery of classes of non-coding RNAs, the primary focus of Genetics was essentially on variation of DNA aiming at elucidating biological pathways perturbed in diseases. Recently, extensive attention has shifted towards the study of posttranscriptional RNA modifications occurring in both protein-coding as well as non-coding RNAs, revealing a novel and finer layer of complexity in gene regulation. This, in turn, has led to the birth of the novel field of ‘Epitranscriptomics’. The recent increase of applications of high-throughput sequencing technology (HTS) has allowed the unprecedented opportunity to identify on a transcriptome-wide scale, millions of RNA modifications in human genes, counting today more than 140 distinct types such as: methylation (e.g. m6A, m1A, m5C, hm5C, 2’OMe) methylation (e.g. m6A, m1A, m5C, hm5C, 2’OMe), pseudourylation (?), deamination (e.g. A-to-I RNA editing). The scope of this Research Topic was to collect both reviews and research articles addressing the wet lab approaches and bioinformatics methodologies necessary to aid in the identification of novel RNA modifications and characterization of their biological functions. Among the articles embracing the aim of the Research Topic, we have collected four original research and methods articles, five reviews, and a technology article.