At first glance you’d be reminded of the Old Book Of Lore from the 2016 core set.

But due to several small differences (limited uses, free trigger, and mandatory draw of weaknesses) this is actually Mr Rook in book format. And when you get some use out of it you’ll remember the upside (free draws but you only pay 1 action up front!) as well as the downside (seeing weaknesses).

And you’ll also see the upside to the downside. You’ll tend to get the weaknesses in your deck resolved early and on your terms rather than in middle of a crisis. And those are free bonus draws rather than dead draws. Highly recommend for any deck that can take it.