Strategy guides are instruction books that contain hints or complete solutions to specific video games. The line between strategy guides and video game walkthroughs is somewhat blurred, with the former often containing or being written around the latter. Strategy guides are often published in print, both in book form and also as articles within video game magazines. In cases of exceptionally popular game titles, guides may be sold through more mainstream publication channels, such as bookstores or even newsstands. Some publishers also sell E-Book versions on their websites.
Strategy guides marketed as "official" are written by game distributors themselves or licensed to a specialty publishing house; Prima Games and Piggyback Interactive specialise in writing official guides for various companies. There are also a number of publishers who make unlicensed, "unofficial" strategy guides, and many of today's mainstream publishers began by making such guides.