The book, compiled between 1785 and 1910, the period of feudal Joson dynasty, has 2 375 volumes.

Its compilation was started since the ruling period of Jongjo, the 22nd king of the feudal Joson dynasty.

Jongjo, who became the king in 1777, gave his diary recording his political affairs and private life since 1760 to officials of the central library of the country to let them write a book with his political affairs as the main. And he personally revised the book and named it "Ilsongrok".

Since then, "Ilsongrok" had been edited until the reign of Sunjong, the last king, through Kings Sunjo, Honjong, Choljong and Kojong.

The book contains the records on the daily political affairs of the kings, their orders and instructions and official documents to them from government offices and officials in the capital and local areas, which cover all the fields including politics, economy, military and diplomacy.

The book, now handed down as a copied version, is regarded as a precious document with correctness and reliability as it was written and compiled during the reign of relevant kings.

It is one of the four diaristic national classics of Korea, along with the Chronicles of the Feudal Joson Dynasty and two other books.