The process of self-assembled monolayer (SAM) formation by the spread coating of an octadecylphosphonic acid (OPA) solution onto a mica surface is investigated by atomic force microscopy, When concentrated solutions are employed, a novel mechanism of SAM formation is found: OPA multilayers, mostly bilayers, are initially deposited on the mica surface. As time passes, these large multilayers break apart and evolve into disorganized monolayers. Following a rapid evolution, such monolayers are found to transform into well-ordered OPA self-assembled monolayers.