This pdf is 13 pages long, 1 page front cover, 1 page advertisement, 2 pages editorial, 1 page ToC/foreword, 1 page SRD and 1 page back cover, leaving us with6 pages for content, so let's check this out!
This pdf, much like the others in the excellent Dungeon Dressing-series, kicks off with a discussion of the object-class at hand, to be more precise, about component materials and pre-calculated HPs, breaking DCs as well as notes on construction before we delve into a table that provides us with a total of 31 different characteristic appearances that include being part of brass reliefs, being covered with programmed images and even featuring an arrow slit. Where applicable, the entries also features all necessary rules for e.g. arrow slits etc., making these additions work as seamlessly as your secret door's hopefully hidden.
75 entries are provided for dressings and features - from a human corpse pinned to the wall with a spear to airtight secret doors that have a bull rush of air erupt when opened to cosmetic features like perfume, old paint denoting the door's existence. Among my favorite ones would be a secret door that is covered in plaster depicting two lovers, literally ripping the plaster (and thus the lovers) apart when opening the doors. Nice symbolism that can easily be used by a bright DM.
Of course, there also are 6 traps to secure secret doors, including a door-mounted crossbow, buckets of acid (in a cruel twist of the traditional prank) and a rather devious one that actually arms a second trap when disabling an obvious one. Other devious traps combine poison gas with clever illusions, doors that slam you against the wall and a teleport splitter. The traps range from CR 1 to 9.
Editing and formatting are very good, though not perfect: The second table features two entries for the number "3", omitting the 4. Layout adheres to Raging Swan Press' elegant b/w-2-column, no-frills standard and comes with full bookmarks as well as two versions, one optimized for screen-use and one to be printed out.
The Dungeon Dressing-series is usually a joy to review: Nice content, consistently high quality and high usefulness for any DM and this issue is no different in that regard, providing us with cool dressing and tricks to spice up our secret doors - just don't get carried away like the designers of Ultima IX's Castle British. ;) Kidding aside, another great installment and thus I'll settle for a final verdict of 5 stars, only omitting my seal of approval due to the one glitch and the fact that I would have liked a longer table on secret door appearances.