Scientific drilling is an important means to collect samples and data that cannot be readily collected from surface outcrops. A series of ocean drilling projects, from the Deep Sea Drilling Project( DSDP; started in 1968) to the Integrated Ocean Drilling Program(IODP), has achieved significant results in earth science, which include verifying the theory of Plate Tectonics and settling the dispute on the mass extinction at the Cretaceous/Paleogene boundary. In 1996, about 30 years after the start of DSDP, the International Continental Scientific Drilling Program(ICDP), an international cooperation project for on-land drilling, was initiated. In Japan, the Unzen Drilling Project was first conducted with the help of funding from ICDP( see Nakada’s paper in this issue). However, many fewer scientists are inter-ested in ICDP than in IODP. A limited number of ICDP proposals have been submitted by Japanese scientists. To provide information on the scientific significance of ICDP and other on-land scientific drilling to the Japanese earth science community, the Japan Drilling Earth Science Consortium( J-DESC) Continental Drilling Section is publishing this special issue. We hope it will stimulate Japanese communities and increase their interest in on-land scientific drilling including ICDP. This special issue comprises nine papers, the scientific contents of which will be very useful for on-land scientific drilling in Japan. The first paper, by Niitsuma( 2013), looks at the history of continental scientific drilling projects in the latter part of the 20th century prior to the launching of ICDP. Representative examples include super deep drilling projects conducted at the Kola Superdeep Well(Russia) and Kontinentales Tiefbohrprogramm( KTB() Germany) sites. These projects developed technologies for preventing borehole break-outs and drilling under high-temperature conditions. However, the results obtained by the projects contradicted scientists’ expectations and highlighted a lack of under-standing of the Earth’s interior. Scientific drilling projects were planned before ICDP started in Japan, but most have not yet been performed. All the proposed drill sites are introduced. The second paper, by Urabe( 2013), reviews the history and performance of ICDP, in particular focusing on those of Japanese scientists. ICDP was initiated to promote continental scientific drilling projects globally and enhance interna-tional cooperation. Although ICDP has a much smaller budget and organizational structure than ocean drilling projects such as IODP, its performance has been excellent. As he points out, a serious issue is that principal investigators( PIs) are required to fund large drilling costs if their proposals are accepted. In spite of such difficul-ties, continental drilling will become increasingly important when using scientific results to estab-lish a sustainable future for human society. Nakada(2013), a PI of the Unzen Drilling Project, reviews the scientific results of volcano drilling and its future prospects. Drilling into volcanoes is best suited for understanding subterranean three-dimensional geometrical and