  This chapter deals with atom-wall interaction occurring in the "long-range"
regime (typical distances: 1-1000 nm), when the electromagnetic fluctuations of
an isolated atom are modified by the vicinity with a surface. Various regimes
of interaction are discussed in an Introductory part, from Cavity Quantum
ElectroDynamics modifications of the spontaneous emission, to Casimir effect,
with emphasis on the atom-surface van der Waals interaction, characterized as a
near-field interaction governed by a z-3 dependence. The major part of the
Chapter focuses on the experimental measurements of this van der Waals
interaction, reviewing various recent techniques, and insists upon optical
techniques, and notably selective reflection spectroscopy which is particularly
well-suited when excited atoms are considered. A review of various experiments
illustrates the specific effects associated with a resonant coupling between
the atomic excitation and surface modes, from van der Waals repulsion to
surface-induced resonant transfer, and with anisotropy effects, including
metastability transfer induced by a quadrupole contribution in the interaction.
The effects of a thermal excitation of the surface -with a possible remote
energy transfer to an atom-, and of interaction with nanobodies -which are
intrinsically non planar- are notably discussed among the prospects.
