Volume 25, entitled Modern Avenues in Metal-Nucleic Acid Chemistry, of the series Metal Ions in Life Sciences (MILS), provides a timely overview of selected relevant developments in a field which previously had a pronounced focus on fundamental chemistry aspects such as coordination principles, structural chemistry, and consequences for biological processes and disease-related medicinal issues. More recently, also as a consequence of the advent of supramolecular chemistry, advancements in nanochemistry, and new bio-analytical methods, novel aspects of this field have emerged. MILS-25 gives a state-of-the-art account on the present state of research in this field, addressing, among others, porous materials, non-covalent interactions, stimuli-responsive bioconjugates, DNA-templated metal arrays and nanoclusters, genotyping, guanine quadruplexes, and riboswitches. It consists of 15 comprehensive chapters with over 1600 citations, 160 figures (90 of them in color), with key contributions from 40 international experts from Europe, Asia, and America. It is an essential resource for scientists from numerous disciplines, ranging from materials science to biochemistry, by way of classical chemistry and physics.