What were they thinking.

It needs to proc once to break even in actions, and 3 times to break even in resources in the ideal operating environment. That's placing and subsequently pulling at least 6 curses (and not cancelling them) AFTER the tome has been played, each of which on a subset of Insight events. All that to break even INSIDE a scenario... not counting the prerequisite quest or the 8xp playset. And it has to compete in the hand slot.

lol?

This card is better than it seems. Yes, you read that right.

It is an intriguing build-around for Rex Murphy decks. First, remember that you have to Resolve the tokens, not just Reveal them (so no Rod of Carnamagos shenanigans). Rex’s infamous Rex's Curse makes you not only Reveal but also Resolve tokens TWICE per test. But wait, there’s more! After you Resolve the tokens during the initial Rex's Curse check, you return them to the bag. This means that you can draw them again on the second part of the test, giving you a better chance of drawing the tokens and adding even more Secrets to the Cryptic Grimoire.

Once you have set up your assets and got the game rolling, you can expect to perform 2-3 Skill tests per round, including Investigate and Treachery checks. With Rex's Curse, you get to Resolve tokens 4-6 times per round (assuming you keep succeeding in the tests so you don’t shuffle Rex's Curse back into the deck). That’s plenty of chances to add Secrets to the Grimoire when using a deck. And what can you do with the Grimoire’s discounted Fast Insight cards? EVEN MORE Skill tests, each giving TWO chances to Resolve tokens (though most relevant Insight cards are testless). This card turns Rex's Curse into a signature boon.

There is, of course, a risk of failing Skill tests due to the tokens, but even then, you are not left high and dry because at least you get the Secrets to play your Fast Insight cards to make up for the failed test.

In addition to some Insight cards, Rex Murphy can generate tokens with Gabriel Carillo, and by throwing away his stuffy nerd glasses and replacing them with new sparkling Prismatic Spectacles.

Some notable Insight cards for Rex are Rex’s own signature card Search for the Truth, Burning the Midnight Oil, Deep Knowledge, Delve Too Deep, Drawn to the Flame, Existential Riddle, Preposterous Sketches, Stirring Up Trouble, and Ravenous Myconid's Uncanny Growth.

After playing out a campaign with parallel Rex, I've come to report this card is still really bad. It has so many downsides for the chance of some kind of positive.

• The untranslated version still costs 3 resources to play, still takes up a hand slot, and unless you're parallel Rex with an Analysis in hand, it's one of the more difficult unlocks to get while also having lasting negative effects via curses in the bag.
• You have to spend 4xp on it, or 8xp if you're going for the set, which if you're going to the trouble of doing the side-quest, you're probably going for the set. If you're parallel Rex, you can at least take Shrewd Analysis and cheat the upgrade because it's the only viable upgrade.
• The Grimoire becomes less and less worth drawing the further you get into a scenario because you'll have less and less time to draw curses and therefore the value you get from the Grimoire becomes worse and worse.
• If you play the Grimoire, you're down 3 resources and an action. Another major downside is it's a large drop to do nothing. You see no immediate benefits. So you have to resolve 4 curses and play two insights for the Grimoire to start looking like it's worth it. At that point you'll be down one resource but up one action. 3 insights played is where you can actually say the Grimoire was definitely worth playing, but for that to happen, you have to individually resolve 6 curses, and have drawn into three insights which you held onto this whole time.
• The fact you have to hold onto insights is another major downside. You might have the Grimoire in play with 0 charges, but you're free now to do a big activation which includes some insights in your hand. Is it really worth it to hold onto them and take the chance you'll be free later to do the same big activation?

Finally, you want to take the Grimoire because you want to save resources and actions on insights. At least in the case of parallel Rex who seems to be a major contender for the Grimoire...

• 14.5/45 possible insights are already 0 resources (I counted 1/2 if one upgrade was 0 but another wasn't. There were 3).
• 14/45 possible insights are already fast.

So you get a lot of overlap where you actually aren't getting the full benefit of the Grimoire's +1 resource, +1 action effect, meaning you may have to realistically play 4-5 insights for it to actually be worth it! You might say, "Oh, well I'll just spec my deck so I'm always saving on both," but there are so many 0 cost and/or fast insights that you'd just be kneecapping yourself by limiting your options at that point in order to make the Grimoire feel not terrible.