Write some case notes into a letter
From Fallen London Wiki
| Spoiler warning! This page contains details about Fallen London Actions. |
From: Epistolary Matters
The Neath has seen entirely new categories of crime emerge.
Game Instructions: The recipient can read it to increase their Watchful.
Unlocked with 
Watchful 80, 
5 x Journals of Infamy
Locked with 
A Letter, Ready to Mail, 
Establishing Social Relations
Success
Putting words in order
It takes time to arrange disparate facts and realizations into a coherent narrative. Red herrings must be trimmed; events and personages introduced at the proper time.
You have a letter ready to be mailed. (Sets 
A Letter, Ready to Mail to Shared Case Notes)
You've lost 5 x Journal of Infamy
Recipient's Benefit: Read shared case files
