In South Korea, ground-based total ozone observation has been operated since 1984 by using a Dobson spectrophotometer at the Wolbong Observatory of Yonsei University in Seoul. This year marks the 40th anniversary of the observation by the Dobson pectrophotometer. We introduce the detailed history of the Wolbong Observatory, the oldest ozone monitoring site in Korea. In addition, we provide an overview of the instrument updates of the Dobson spectrophotometer and the processes involved in instrument alibration and data quality control. It also reviews various research activities related to using data by the total ozone and ozone profile observation from the Dobson pectrophotometer over the past 40 years. Long-term observational data have been used not only as a reference ataset for the validation of other remote sensing instruments, but also an important dataset for the study of long-term trends in the ozone layer and the spatio-temporal change of ozone. The Dobson spectrophotometer has produced observation datasets of high quality for four decades, and it still consistently provides homogeneous and reliable data on total ozone and vertical profile information. It is expected to continue playing a significant role in ozone research in Korea.