Remember, if you haven't used our clues pages yet, check out the instructions here to learn how they work and how to best utilize them.
Hint 1
Solving this is a matter of frequency.
Hint 2
After careful analysis, you'll notice you have everything you need!
Hint 3
How many times did you count the letter "Q"? Does that number appear anywhere else?
Hint 4
Once you've correlated your key. It's just a matter of substitution.
Solution
This message is a substitution cipher, meant to be solved via frequency analysis. This can be done from the ground up, or can be done using the letters and numbers on the front of the card. These letters and numbers correspond to the letter frequency of the plaintext message.
"The English Language like every written tongue has a couple of flaws. Regardless, the ability to utilize and manipulate it with fluency is certainly an important art." -- Anna Eve Massam
Hint 1
Interesting Start, But No
Hint 2
International Standard... Books, Numbers
Hint 3
Compare and contrast. How do your titles line up?
Hint 4
Five ISBNs and five titles on the spines.
Hint 5
In each set of books you have, one should stand out.
Solution
The ISBNs give you five book titles that include a location, along with other words. The covers on the front of the card show five partial book titles. Cross referencing the ISBNs to the titles on the front shows that the second book shown, and the second ISBN listed don't match up.
This gives two important pieces of information - the location from the ISBN, 'Minneapolis', as well as the department from the spine, 'Linguistic Studies'
Hint 1
Mirror Images
Hint 2
Be sure to reflect on what you should do.
Hint 3
Forwards, backwards, it makes no difference.
Hint 4
dnuora ti nrut.
Solution
Each stamp has two digits, and depicts a mirror. To find the date you need, invert each pair of digits. So, 41 becomes 14 and 14 becomes 41, to yield the full date of '1441'