The Warcraft II: Tides of Darkness The Official Strategy Guidebook was published by Prima Publishing on January 17, 1996.
Description from Amazon
No matter which side you choose, WarCraft II: Tides of Darkness—The Official Strategy Guide will keep you on the victorious end of the pounding, pillaging, and plundering. From Zeppelins to Gryphon Riders, it's easy to build impermeable defenses and launch brutal assaults when you've got:
Battle strategies proven to decimate enemy forces
Sound advice for building a strong and prosperous community
The book was written using Warcraft II beta material and does mention some things that were cut from the game, such as Gul'dan being captured by the Alliance in the The Prisoners mission and the humans having already built oil platforms before the Second War.