This book is a research reference book for conducting event study. Event study is a popular and useful tool in measuring the impact of an event in accounting, economics and finance. This method, event study, attempts to measure the valuation effects of an event, such as a merger or earnings announcement, by examining the response of the stock price around the announcement of the event. One underlying assumption is that the market processes information about the event in an efficient and unbiased manner. Thus, we should be able to see the effect of the event on prices.