The role of the creation and decay of excited states in interfacial processes is highlighted. The work includes non-adiabatic effects, ultrafast processes, reactions induced with scanning probes and the decay of excited molecular states at surfaces. Faraday Discussions documents a long-established series of Faraday Discussion meetings which provide a unique international forum for the exchange of views and newly acquired results in developing areas of physical chemistry, biophysical chemistry and chemical physics. The papers presented are published in the Faraday Discussion volume together with a record of the discussion contributions made at the meeting. Faraday Discussions therefore provide an important record of current international knowledge and views in the field concerned.