This card is one of the most insane cards seen to date. Combined with Sleight of Hand, Knowledge is Power and/or Scavenging you have a monster card.

• It gets up 2 missing clue from anywhere
• It kills 3 health enemies
• It draws up to 6 cards
• Or act as 6 Unexpected Courage

all as actions, combined with Sleight of Hand you can use it for an entire turn for only 1 resource. With Knowledge is Power you can activate anyone of it's abilities once. Once those cards is used up play it and use it again and then once it is spend overwrite it so it gets discarded and fetch it back using Scavenging.

Use this with Rex Murphy and only 5 XP you can get all of the above and with Research Librarian and/or Mr. "Rook" ensures that this combo is almost a sure thing.

It is not even unique so all seekers can get one in multiplayer.

Edit: Got the actual pack now and it turns out that the above was not good enough, so seekers got one more tool to recycle it using Library Docent and an extra tool to find it with Whitton Greene.

Nice combo with Minh Thi Phan :

1) put in play Scavenging (2) and Glyphs (+1 clue / 2 pts of success)

2) investigate with Glyphs, commit The Necronomicon

3) succeed by a wide margin (you are investigating with a skill value of 10+ ...)

4) use Scavenging (2) to either take The Necronomicon back in your hand or play it for 3.

Of course it's a 10 XP combo and each test can be failed but it's a fun way to use 5 slots in a deck with cards that can be useful outside of this combo.

tl;dr Well Prepared, Archaic Glyphs (Guiding Stones), The Necronomicon is a crazy combo that can trivialize clue-gathering.

In longer form...

This card is a core piece of my favorite Arkham LCG deck: Joe "The Book" Diamond. It's a basic three-card combo deck that can perform absolutely mind-boggling feats of clue-gathering and save tons of actions.

So we've got the Nomnomicon. What's the rest of this combo? It's pretty simple, but at the time of writing only Joe can pull it off. You just need Archaic Glyphs and Well Prepared! With the Necronomicon this comes out to 15 XP total. Triggering Well Prepared on the Necronomicon gives you +5 to Intellect, which with nothing else is already a 9-value stat. Assets and other commits, as well as skill boosts from the Necronomicon, can easily raise you enough to pick up 3 or more clues reliably per action.

Plus, this card just straight value in Joe. It supplements free clues from his Hunch deck, damage against enemies, and can be refilled/used for free via Truth from Fiction, Astounding Revelation (if you're running searches), and Knowledge is Power.

You won't always need to spend four Nomnomicon charges, exhaust two copies of Well Prepared, and commit four Intellect icons from hand in order to succeed an Archaic Glyphs investigation by 23 and pull 12 clues off of a single location with a single action. But when you do, the Well Guided Necronomicon is here to help!

I really don't like how this card has no downside thematically. There really should -2 to max sanity, draw encounter card, add a madness or something to reflect the mind-shattering properties of the book.

In addition to being a theming failure (@fistofyogsothoth covered this nicely already), this card was already too strong when abused alongside recursion effects like Scavenging or Library Docent, or with any of the other obnoxious combos people have already reviewed nicely.

With the Drowned City gator cards being released, the possible combos for this card have gotten even more disgusting: enter Library Pass. Combo this with Scroll of Secrets and now you can, with ZERO REQUIRED, do the following:

• Put Necronomicon on Library Pass
• Use all 6 charges (often just grabbing 2 clues for free, or doing 3 free damage and drawing 2 cards)
• Don't pay the 1 resource and let the book go to the bottom of your deck
• Use Scroll of Secrets(3) during any window between now and the start of your next turn to put Necronomicon back in your hand (and maybe throw away a weakness while you're at it)

3 rotations of Necronomicon not enough to break the scenario? No problem, recur your Scroll with Library Docent, or put more secrets on it with Eldritch Sophist (or any other secret-adding card), or use Ariadne's Twine.

This card needs to be taboo'd differently; until then I will not be playing it unless I'm in the mood for a free campaign win.

There are a few interesting ways this could be balanced. Perhaps something like

Cost: 10r This card costs 1 less resource for each horror on your investigator FORCED - When you play this card, take 2 horror

I'm also partial to the suggestion that you add a Madness to your deck when playing this. Dark secrets have dark prices!!