Abstract: This invention provides rapid, accurate and repeatable alignment of components in three spatial coordinate directions to within about .+-.10 .mu.m. It comprises a two-stage kinematic mount and a corresponding two-stage mountable module, each having a macrostage for initial alignment and a microstage for further, high accuracy alignment. The microstage of the mount preferably has either three alignment pins or three constraints and the microstage of the mountable module likewise preferably has either three pins or three constraints, so that the constraints of one component receive the pins of the other. A compliant layer is positioned between the microstage and macrostage of the mountable module. This invention further includes two-stage mount and mountable modules incorporating optical, electrical, mechanical or fluidic elements. In a preferred embodiment, the microstage module has a V-groove fluid flow channel suitable for use in optical flow cytometry.