The material for the Collected Works of T'oegye began to be collected and recorded in 1571, one year after Yi Hwang(1501-1570)'s death. It was first published some thirty years later in 1600(the official Gyeongja Edition), after undergoing years of painstaking efforts at complicated editing and revising. The records of the Master were first collected in the original manuscript of 1579, named the Collected Works of Master T'oedo, which gave rise to the second draft in anthology form named the Collected Works of Master T'oegye(Original Text Version) in 1586. This second draft(original text version) underwent revision to form the Collected Works of Master T'oegye(Revised Version) in 1588. This revised version of the second draft then gave rise to the second critical anthology edition in 1590. From this second anthology edition the officially sanctioned decisive contemporary critical edition was made in 1599, known as the Collected Works of Master T'oegye(Standard Version). The decision to divide the works of Yi Hwang into the Inner Chapters, the Miscellaneous Chapters and the Outer Chapters in accordance with the date of composition of the respective works by the author was made early in the process of editing. This decision was facilitated by the existence of hand-written versions of Yi Hwang's poems, which the author had personally edited. The Collected Works of T'oegye follows the overall layout and systemic structure of the Complete Works of Master Zhu(Zhu Xi), with the exception of the section on letter correspondence, which does not follow the latter work's content-oriented classification in its editing strategy. Rather, the classification of letters in the Collected Works of T'oegye is based on personalities to whom the correspondence is addressed in addition to their content. Thus, the letters are classified according to four types of corresponding personalities, namely Contemporary Worthies, Old Acquaintances, Fellow Scholars and Students, and Family Members, respectively. The above style of classification in the process of editing was first adopted by Kim Seong-il ("Hakbong":1538-1593) and Yu Seong-ryong ("Seo'ae":1542-1607), who supervised the correction and revision of the original manuscripts. It was also adopted in turn by the final editor, Jo Mok ("Wolcheon":1524-1606). This differing style of classification is the most marked difference between the Collected Works of T'oegye and the Complete Works of Master Zhu. After the publication of the Collected Works, its layout and classificatory system influenced the editing of the works of other contemporary scholars in Joseon-dynasty Korea. However, in spite of the innovation in the classificatory system in the editing of the letters, when published the first official edition of the Collected Works of T'oegye, or the Gyeongja Edition, was beset with many editorial problems. In fact, Yu Seong-ryong is said to have been critical of it as being an edition that represented an engraving of the draft version of the text. If the publishing had been rushed due to the War with Japan(1592-1598), there ought to have been a rigorous process of correction afterward, including supplementary engravings. The fact that this was neither followed through at the time, nor addressed in later re-publication efforts has meant that the problems have remained to the present day, due to the conservative tendency in scholastic circles to adhere stubbornly to existing tradition.