This dissertation delves into corporate behavior around the 1997 Asian crisis which had a significant effect on Korean firms and the economy. It includes three main parts. Chapter 2 looks at corporate governance and firm value in Korea. Since the Asian crisis the corporate governance issue has changed remarkably in Korea. The Korean government has amended many provisions regarding this issue. This paper first surveys the series of amendments to associated provisions and laws. Then we investigate the relationship between corporate governance and firm value using the long-term event study method to see how these amendments affect firm value. Chapter 3 examines the structural changes of seventy firms in the Korean Stock Exchange around the Asian crisis under the assumption that break dates are unknown. The Korean economy was broken up by the crisis in 1997 and then it took some years for it to be recovered through the effort of the government and firms. Thus, it is natural to think that firms? specific parameters might have been changed reflecting firms? efforts to survive the crisis. This paper assumes that the structural break dates are unknown. Then we estimate them and test for structural change of unknown timing around the crisis on each of seventy firms in the KSE. Chapter 4 is an empirical investigation of insider trading. The Korean economy had a hard time during the Asian crisis. To restructure and reform the economy the Korean government implemented IMF guidelines which it agreed to follow when receiving IMF?s $57 billion rescue bailout package. In this chapter we evaluate the iv restructuring and reform in the past decade in terms of the cleanliness of the stock market in terms of insider trading. Considering the provisions regarding insider trading in Korea, it is hard to quantify the degree of insider trading using only reported insider trading data. Thus, this paper adopts the event study method to analyze the degree of insider trading before and after the reforms. We find that there is evidence suggesting that there was insider trading before the crisis reforms which was subsequently (or eliminated) following these reforms.