The clear and easy-to-follow protocols collected here illuminate the molecular basis of protein–nucleic acid interactions. Use them successfully to reveal the location of the DNA binding site, the strength and specificity of a binding, the identities of individual groups on the actual bases involved in binding, and the specific amino acid residues of the protein that interact with the DNA. Some of the techniques can even be used to identify previously unknown DNA binding proteins from crude cell extracts, thus empowering you to make groundbreaking advances in your work.