With the continuing discovery of extrasolar planets and an expectation that the majority<br /><br /><br />
of solar-type stars reside in binary or multiple systems, planetary formation in binary systems has become an important matter. Recent theoretical studies have predicted that circumbinary planets (i.e., those orbiting two stars which are tightly bound gravitationally)<br /><br /><br />
can form and survive over long time scales. The presence of a third body orbiting an eclipsing binary causes a periodic variation of the eclipsing period due to the increasing and decreasing light-travel times (LTT) to the observer. Because the historical data base is very large and for many binaries very long, we can potentially discover numerous eclipsing systems with circumbinary companions. Also, it should be possible to detect additional planets or exomoons by using transit timings in systems with known transiting planets. In this talk, I will present the discovery of a circumbinary planetary system orbiting around a close binary system, based on historical eclipse timings.