(Part 2) Top products from r/codes

Some pretty good reads on the subject:

Top Secret: A Handbook of Codes, Ciphers and Secret Writing https://www.amazon.com/dp/0763629723/ref=cm_sw_r_awd_WF1Dub0WN55RY

The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography https://www.amazon.com/gp/aw/d/B004IK8PLE/ref=aw_ss_kndl_dp/

Codebreaker: The History of Codes and Ciphers https://www.amazon.com/dp/0802715478/ref=cm_sw_r_awd_OH1Dub103RXB7

And, believe it or not,

Cracking Codes and Cryptograms For Dummies https://www.amazon.com/gp/aw/d/B005CB22A8/ref=aw_ss_kndl_dp/

You also might check your local newspaper for "Cryptoquote." It's a daily quote that uses a different cipher each day. Great for practice!

If you're looking for a book that teaches you about codes and practical codebreaking, here are two greats: Cryptanalysis: A Study of Ciphers and Their Solution, by Helen Fouché Gaines and Codes, Ciphers and Secret Writing, by Martin Gardner.

For a historical look try The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography, by Simon Singh. I really loved that one!

I found the site, here are some first observations

• 12 32 35 21 24 from 0001.txt gives you a five-number sequence which could be related to your 5 x 5 grid puzzle
  
• Paul's address 80 E. 11th Street in NYC is a real address of a building called the St. Denis. Furthermore, on the outside of that building is R O L A N D ... one huge letter in each of six windows. Probably not a coincidence, it may be that ROLAND is needed somewhere in this game
  
• The telephone numbers of Jonah, Elias, Paul, and Hermann are actually ISBN-13 numbers of science fiction books by Isaac Asimov. I was looking to see if they are real phone numbers in a certain nation, then realized they are not, they are ISBN, and searching each number yields an Asimov book
  
• 0553803735 = Second Foundation (Jonah's telephone number)
  
• 0553803700 = I, Robot (Elias' telephone number)
  
• 0553803719 = Foundation (Paul's telephone number)
  
• 0553803727 = Foundation And Empire (Hermann's telephone number)

"Assassin's Apprentice (The Farseer Trilogy, Book 1)", by Robin Hobb.

https://www.amazon.com/Assassins-Apprentice-Farseer-Trilogy-Book/dp/055357339X

This puzzle book from last year was written by the staff of GCHQ who know a thing or two about codes.