Report on the Scientific Results of the Voyage of HMS Challenger
The report detailing HMS Challenger's journey and scientific findings took almost 20 years to publish in its entirety, the final of its 50 volumes at last seeing print in 1895. This monumental task was performed by the specially-created Challenger Office in Edinburgh, under the supervision of Sir Charles Wyville Thomson, the director of Challenger's scientific staff (until his death in 1882, when one of the expedition's other scientists, John Murray, took over).
While 19 years seems a very long time to finish a report of this nature today, HMS Challenger's discoveries were completely unprecedented in scope. Three years' worth of oceanographic data - a very new science in 1876 - needed to be collated and analyzed, not to mention the 4,700 newly discovered species of which specimens were sent to experts across the world for examination. Given the limitations of travel, communication, and publication in the late 19th century, it is perhaps astounding that the Report was completed in as short a time as it was.
Cornell University Library possesses a print copy of the Report, which can also be viewed online through the Biodiversity Heritage Library.