We describe high-resolution lithography based on transfer of a pattern from an elastomeric "stamp" to a solid substrate by conformal contact: a nanoscale interaction between substrate and stamp on macroscopic scales that allows transport of material from stamp to substrate. The stamp is first formed by curing poly(dimethy1 siloxane) (PDMS) on a master with the negative of the desired surface, resulting in an elastomeric solid with a pattern of reliefs, typically a few microns deep, on its surface. The stamp provides an "ink" that forms a self-assembled monolayer (SAM) on a solid surface by a covalent, chemical reaction. Because SAMs act as highly localized and efficient barriers to some wet etches, microcontact printing forms part of a convenient lithographic system not subject to diffraction or depth of focus limitations while still providing simultaneous transfer of patterned features. Our study helps to define the strengths and limitations of microcontact printing with SAMs, a process that is