The Fireproof Secret Diary is a crafting ingredient that was updated in the June 27, 2012 Patch. It was originally added in the June 19, 2012 Patch, as the Secret Diary. It is an old, red book with a flame design framing the partially singed cover. The book is bound closed by a golden-colored clasp lock. Along with the Barely-Melted Capacitor, this item was not visibly affected by the Pyromania Update, and was not removed in the July 11, 2012 Patch.
For the Scream Fortress 2013 event, the Secret Diary can be equipped in every class's Action Slot, which can only be used to replace the Spellbook Magazine or the Fancy Spellbook to cast spells.
June 19, 2012 Patch
- [Undocumented] The Secret Diary was added to the game.
June 20, 2012 Patch
June 27, 2012 Patch (Pyromania Update)
- [Undocumented] The Secret Diary is one of the two Mysterious Treasures, along with the Capacitor, not incinerated into a small pile of ash. Despite the obvious fire damage to the bottom right corner of the cover, it was renamed Fireproof Secret Diary, and it is not valid as one of the crafting ingredients for the Pile of Ash.
March 12, 2013 Patch
- [Undocumented] Fixed background errors in the Fireproof Secret Diary backpack icon.
October 29, 2013 Patch (Scream Fortress 2013)
- Equipping the Eliminating The Impossible set will change the Secret Diary description to "the deeds of hellish cruelty and none the wiser", with random characters removed, which is a part of a quote from the "The Adventure of the Copper Beeches" short story, part of The Adventures of Sherlock Holmes collection. When combined with the other items added in the June 19, 2012 Patch, the full quote reads "Think of the deeds of hellish cruelty, the hidden wickedness which may go on, year in, year out, in such places, and none the wiser."
Level 1 Secret Diary
Unlike other games we could mention, owning this won't trigger a sound file narrating secret diary entries. Why? Because we RESPECT THE PRIVACY of our characters. What are they hiding? Truly we live in MYSTERIOUS TIMES.