I was thinking about what book to post today. I decided that since there have been more Star Wars ones this year I would even it up with another AD&D book.
On that note, here is the Wilderness Survival Guide.
This book is useful for players and DMs/GMs adventuring in the outdoors from frozen wastes to tropical forests.
It covers the effects of the wilderness on characters, designing a campaign map, a system for determining weather, and more.
-Dean