From ozbargin posted by dealbot:
GOG will be offering some free goodies to celebrate the Witchercon(witchercon.com) event.
Available until 12/7 5pm. UTC (5:00 am Tuesday, in, Wellington)
The following will be part of the freebie(thewitcher.com) -
The World Of The Witcher: Video Game Compendium ebook (Kindle version - $29.33)(amazon.com.au)
The Witcher: Volume 2 - Fox Children ebook (Kindle version - $14.60)(amazon.com.au)
Video Game Show – The Witcher 3: Wild Hunt Concert
4 GWENT cards - Sunset Wanderers, Yennefer of Vengerberg, Ciri, Vesemir: Mentor
The Witcher: Enhanced version when you download GOG Galaxy(gog.com)
Credit to mydealz
great game, be sure to load those 'essential' mods if its your first time