Buried in the Almanac was a hidden message.

From RPO, "Scattered throughout the text of the Almanac were a series of marked letters. Each of these letters had a tiny, nearly invisible «notch» cut into its outline. I’d first noticed these notches the year after Halliday died. I was reading my hard copy of the Almanac at the time, and so at first I thought the notches were nothing but tiny printing imperfections, perhaps due to the paper or the ancient printer I’d used to print out the Almanac. But when I checked the electronic version of the book available on Halliday’s website, I found the same notches on the exact same letters. And if you zoomed in on one of those letters, the notches stood out as plain as day.

Halliday had put them there. He’d marked these letters for a reason.

There turned out to be one hundred and twelve of these notched letters scattered throughout the book. By writing them down in the order they appeared, I discovered that they spelled something. I nearly died of excitement as I wrote it down in my grail diary:

The Copper Key awaits explorers

In a tomb filled with horrors

But you have much to learn

If you hope to earn

A place among the high scorers"