It has been far more difficult to obtain material for compiling the history of the past five centuries. By unwritten law the history of no dynasty in Korea has ever been published until after its fall. Official records are carefully kept in the government archives and when the dynasty closes these are published by the new dynasty. There is an official record which is published under the name of the Kuk-cho Po-gam but it can in no sense be called a history, for it can contain nothing that is not complimentary to the ruling house and, moreover, it has not been brought down even to the opening of the 19th century. It has been necessary therefore to find private manuscript histories of the dynasty and by uniting and comparing them secure as accurate a delineation as possible of the salient features of modern Korean history. In this I have enjoyed the services of a Korean scholar who has made the history of this dynasty a special study for the past twenty-five years and who has had access to a large number of private manuscripts. I withhold his name by special request. By special courtesy I have also been granted access to one of the largest and most complete private libraries in the capital. Japanese records have also been consulted in regard to special points bearing on the relations between Korea and Japan. A word must be said in regard to the authenticity and credibility of native Korean historical sources. The Chinese written character was introduced into Korea as a permanent factor about the time of Christ, and with it came the possibility of permanent historical records. That such records were kept is quite apparent from the fact that the dates of all solar eclipses have been carefully preserved from the year 57 B.C. In the next place it is worth noticing that the history of Korea is particularly free from those great cataclysms such as result so often in the destruction of libraries and records. Since the whole peninsula was consolidated under one flag in the days of ancient Sil-la no dynastic change has been effected by force. We have no mention of any catastrophe to the Sil-la records: and Sil-la merged into Koryŭ and Koryŭ into Cho-sŭn without the show of arms, and in each case the historical records were kept intact. To be sure, there have been three great invasions of Korea, by the Mongols, Manchus and Japanese respectively, but though much vandalism was committed by each of these, we have reason to believe that the records were not tampered with. The argument is three-fold. In the first place histories formed the great bulk of the literature in vogue among the people and it was so widely disseminated that it could not have been seriously injured without annihilating the entire population.