A Review of the Current Status of Follow-Up Techniques to Study Known Extrasolar Planets

I present a review of observational efforts to study known extrasolar planets by methods that are complementary to the radial velocity technique. I describe the current state of attempts to detect and characterize such planets by astrometry, by reflected light, by thermal emission, by transit photometry, by atmospheric transmission spectroscopy, by planet-induced chromospheric activity, and by long-wavelength radio emission. With a few exceptions, these efforts have yielded only upper limits. Nonetheless, the diversity and vivacity of these pursuits has rapidly pushed many of these techniques into the realm where realistic models of the planets and their atmospheres can now be confronted.