This chapter discusses that the continuous synthesis of BaSO₄, Ca₃(PO₄)₂, LaCoO₃, BaCeO₃ etc. can be achieved to give a range of particle sizes and morphologies in water-in-TX100/cyclohexane/2-methyl-2-propanol microemulsions and can then be continuously harvested by cooling the microemulsion to 268 K. Surprisingly, the nanoparticles then appear in the organic-rich upper phase. Nanomaterials can be nm sized building blocks for a whole range of applications, e.g. synthetic bone, bone cements, pigments and ceramics provided that their preparation can be scaled up. Microemulsions are of interest in materials preparation as the reactions that lead to particle formation of a characteristic size and morphology occur within dynamic droplets of nm (colloidal) size in which reactant concentrations define the size of solid particles formed.