Prima Games, the U.S.-based DK imprint publishing strategy guides to video games, will stop commissioning new titles immediately, and will be discontinued in spring 2019. As a result, its Roseville, Calif., Indianapolis, and New York offices will all be closed.

Prima, founded in 1990, is the largest publisher in the video game strategy guide sector of the industry. Its demise augurs poorly for other publishers in that space, which has declined significantly since the proliferation of game guide websites over the past decade.

The publisher’s Roseville office will close mid-November, while some members of the Prima Games team, based in the Indianapolis office, will stay until March 2019 to publish any remaining books.

“During a year-long extensive review, many new ways were explored to diversify Prima Games publishing; however, the dynamics for us of this fast-paced landscape have continued to prove difficult,” Ian Hudson, DK’s CEO, wrote in a memo. “This enormously dedicated team has made every effort to turn the business around, but challenging market conditions have unfortunately worked against them.”