This detailed book compiles a series of laboratory protocols covering the most important aspects of R-loop biology. Beginning with a range of methods allowing for the detection of DNA-RNA hybrids, as well as their purification and visualization by electron microscopy, the volume continues with methods based on the use of RNase H-derived tools to detect DNA-RNA hybrids in vitro and in vivo. Several protocols permit studying non-canonical RNA nucleotides in the R-loop context, as well as a number of specific protocols devoted to the investigation of R-loop topology and their functional roles in the biology of mitochondria and telomeres. Finally, a large block of chapters is dedicated to different methods allowing genome-wide mapping of DNA-RNA hybrids in various organisms. Written for the highly successful Methods in Molecular Biology series, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls.