Recent progress in our understanding of the properties of monolayers i
s linked to the development of techniques for their direct visualizati
on. The use of such methods for the determination of phase diagrams of
Langmuir monolayers, both pure substances and mixtures, is described.
Complex optical textures - stripes, spirals, stars - have been observ
ed that are related to those found in liquid crystals, Textures can pe
rsist when the monolayers are transferred to solid supports, allowing
them to be studied by scanning probe microscopy. The transfer procedur
e can be employed to produce stable patterned surfaces.