Dryasdust is was originally a literary moniker used as a derisive label for one who writes boring, flavorless tracts, especially dull historical works composed of stark facts with no feeling for the events and people involved.
The original Dryasdust was Dr. Jonas Dryasdust, a fictitious character that Sir Walter Scott dedicated some of his novels too. His most famous appearance was in the dedication to Ivanhoe (1820), in which Scott presents a lengthy tongue-in-cheek tribute to the genius of Dr. Dryasdust. The esteemed Doctor also appeared at length in Thomas Carlyle's historical work Oliver Cromwell's Letters and Speeches: With Elucidations (1861), where he was roundly pilloried. Between these two, Dryasdust was a fairly well-known and oft-referenced personage in the later half of the 1800s.
These days Dryasdust is more often used as an adjective identifying a stiff, dull writing style, as in "the essay was written in the usual dryasdust manner".