This series began in 1963 and encompassed major studies summarizing knowledge on a subject, often detailing results of geological research. Special reports are considered the “high end” of IGWS scientific publications, requiring a formal review and often having color added to maps or figures to emphasize specific data or to make map data easier to decipher. Because these reports supported the use of color, they were initially commercially offset printed. They were later produced digitally in a PDF format.
