Spin-Polarized Metastable Atom Deexcitation (SPMDS) and Electron Capture (ECS) Spectroscopies probe the exponential tails of electronic wavefunctions extending from the surface into the vacuum, and are consequently extremely sensitive to the surface-vacuum interface. The use of SPMDS to probe the near-surface vacuum magnetization of Ni (l 10) and Fe (l 10) and the dramatic changes that result upon exposure to ambient gases is discussed, as is the use of ECS and Spin-Polarized Electron EMission Spectroscopy (SPEES) to determine the ferromagnetic and critical behavior of surfaces and ultra-thin epitaxial systems.