Free Electron Lasers have capabilities in several regions of the electromagnetic spectrum that are not found in conventional lasers. Among these capabilities are power and tunability in the short-wavelength region of the ultraviolet and soft x-rays and in the mid- and far-infrared region. By using the intra-cavity inverse, Compton scattering high intensity hard x-rays and gamma rays can be generated. For the first time tunable, bright sources of light at each extreme of the spectrum are available for biomedical science. Application from clinical use of gamma and hard x-rays to surgery and chemical imaging of cellular and sub cellular components are possible.