A scanning near-field optical microscope (SNOM) coupled to a UV laser has been used to pattern self-assembled monolayers (SAMs) of photosensitive adsorbates. Using this approach, which we call scanning near-field photolithography (SNP), it is possible to achieve a resolution of 9 nm (nearly 15 times smaller than the conventional diffraction limit) in a SAM of alkanethiols adsorbed on gold. In conjunction with a new etchant, mercaptoethylamine in ethanol, SNP-patterned SAMs have been used as resists to fabricate gold nanostructures as small as 10 nm that have sharp edge definition. Gold nanowires, 60 nm wide, have been fabricated by selective exposure of bilayers of thiol-stabilised gold nanoparticles, followed by rinsing, in a simple two-step process. The principal criterion for achieving high resolution using SNP is the excitation of a specific photochemical reaction in a group distributed with monolayer coverage on a solid surface. This encompasses a broad range of materials. This is illustrated using monolayers of chloromethylphenyl siloxanes adsorbed on silicon dioxide, which may be selectively converted to aldehydes or to carboxylate functionalities to which biological molecules may be attached. DNA nanoarrays have been fabricated that consist of 70 nm DNA spots at 500 nm spacings. These have a density 40 000 times greater than existing DNA chips, while remaining readable by far-field optical methods. Finally we demonstrate the feasibility of carrying out nanophotolithography on aluminium surfaces. Monolayers of aryl azide terminated phosphonic acid adsorbates, which exhibit substantially enhanced ambient stability compared to alkanethiol SAMs, have been formed and selectively functionalised using SNP, in a process 50 - 100 times faster than the alkanethiol patterning process. These illustrations indicate that SNP is a powerful, flexible and straightforward technique for the execution of specific surface chemical transformations.