Experimental methods of studying hypernuclear ground states and continuum states observed in the recoilless A production are reviewed. These two types of hypernuclear states give the most direct information on the A-nucleus interaction. T h e A particle is a unique probe of the nucleus; it interacts strongly with the nucleus and is distinguishable from the nucleons. I n light hypernuclei, gamma spectroscopy is a powerful tool in studying the bound excited states.