Supplements bundled with the "Limited Edition" Dungeoneer's Survival Guide and Wilderness Survival Guide, respectively.  Not sold separately.

Dark & Hidden Ways by William Tracy, Chris Mortika, Grant Boucher, and John Terra
Wild Things by Grant Boucher, David Martin, Chris Mortika, and John Terra

Both of these supplements were actually a marketing gimmick designed to rid overstock copies of Dungeoneer's Survival Guide and Wilderness Survival Guide.  The hardcover manuals bundled within the "Limited Edition" are themselves identical to separately-sold copies, with the exception that their UPC barcodes have been crossed out with black marker (to ensure that the only barcode scanned by retailers is the one on the outside of the supplements' cardstock covers).  Thanks to Devon Hibbs, Shawn Hibbs, and Allan T. Grohe for this info.

Dark & Hidden Ways is a module featuring short adventures / encounters with the denizens of the underworld described in the Dungeoneer's Survival Guide.  It is 32 pages in length, and coverless, though it was bundled with a color cardstock "cover" that is unattached to the module itself.  The cardstock cover actually wraps around both the module AND the hardcover manual, and does not feature any module-specific information on the interior.  And for whatever reason, the first encounter (Dracolich & Drow) ends abruptly on page 8, without listing any stats or treasure for the Dracolich!  On another note, the working title for Dark & Hidden Ways was originally "All Things Dark & Dangerous", but this title never made it to print. (Thanks to Michael Deaton, Aaron Leeder, Chris Nikolauk, James Sinks, and Daniel Thingvold for help with this info).

Wild Things follows the same format as Dark & Hidden Ways, but features the creatures of the outdoor environment detailed in the accompanying Wilderness Survival Guide.  Like Dark & Hidden Ways, it is 32 pages in length, and came bundled with a separate, wrap-around color cardstock cover.  The cover artwork was "borrowed" from Dragon #94. (Thanks to Mike Badolato for help with this info).

Interestingly, both Dark & Hidden Ways and Wild Things bear the 2nd Edition AD&D logo... but their respective hardbacks are for 1st Edition.

Printing Information

There were but single printings of each of these supplements.  As stated above, they were not sold separately, but only found within the "Limited Edition" versions of Dungeoneer's Survival Guide and Wilderness Survival Guide.

Thanks to Matthew Foster for the scan of Dark & Hidden Ways, Leonard Riotto for the scan of Dark & Hidden Ways (front and back), and T.S. McDuffie for the scan of Wild Things (front and back).
 

Dark & Hidden	Dark & Hidden (front)	Dark & Hidden (back)
Wild Things	Wild Things (front)	Wild Things (back)

"SW" values for both supplements assume, of course, that they are bundled in the original shrinkwrap with their color covers and respective hardback manuals.  Lesser conditions indicate a stand-alone supplement, worth considerably less to collectors.

• Dark & Hidden Ways
• Wild Things