Tools shape how we think; when the only tool you have is an axe, everything resembles a
tree or a log. The rapid advances in instrumentation in the last decade, which allow us to
measure and manipulate individual molecules and structures on the nanoscale, have caused
a paradigm shift in the way we view molecular behavior and surfaces. The microscopic de￾tails underlying interfacial phenomena have customarily been inferred from in situ mea￾surements of macroscopic quantities. Now we can see and “finger” physical and chemical
processes at interfaces.