  Adiabatic techniques are known to allow for engineering quantum states with
high fidelity. This requirement is currently of large interest, as applications
in quantum information require the preparation and manipulation of quantum
states with minimal errors. Here we review recent progress on developing
techniques for the preparation of spatial states through adiabatic passage,
particularly focusing on three state systems. These techniques can be applied
to matter waves in external potentials, such as cold atoms or electrons, and to
classical waves in waveguides, such as light or sound.
