Video game strategy guide maker Prima Games is officially shutting down, British publisher DK (formerly Dorling Kindersley ) told Variety on Friday.

“I can confirm that the decision has been made to no longer commission new Prima Games strategy guides and the U.S.-based imprint will be discontinued in Spring 2019,” a spokesperson said via email. “We are in conversations with the Prima Games team and cannot comment on this further at this point.”

The imprint will honor all pre-orders for guides to upcoming games like “Super Smash Bros. Ultimate” and “Anthem” over the next few months, DK told Variety.

Prima Games currently has three offices in Roseville, Calif., Indianapolis, Ind., and New York. The Roseville office will shutter by mid-November, sources affected by the closings told EGM on Thursday. The New York office will close at an unknown date, while the Indianapolis location will continue publishing until March 2019.

The imprint’s guides all feature in-depth content, detailed screen captures, quick-reference tips, and professional strategies. They were a godsend to many gamers of a certain age, back before internet walkthroughs and wikis became de rigueur. Prima Games later tried adapting to an increasingly digital world by offering eguides filled with interactive maps, streaming video, searchable apps, and more.

Prima Games has sold millions of PC and console video game strategy guides since its founding 28 years ago. Its parent company, Penguin Group, bought Random House in 2013 and merged it with its main competitor, BradyGames, making it the largest provider of official video game strategy guides.

There’s no word yet on exactly how many employees will be affected by the closings.