The manual is no longer included in version 1.2.

I imagine that this was an accident, but for now, here's the PDF I uploaded to Archive.org back when I wanted to discuss it with people who don't own the remaster:

https://archive.org/details/system_shock_manual_2023/

• Right click on the game in Steam
  
• Hover over "manage files"
  
• Click "browse local files"
  
• In the game's folder, open Manual.pdf in your PDF viewer of choice

The game does an okay job explaining most aspects of its gameplay on its own, so do you really want to read the manual?

Yes!

Joshua Jenkins did a terrific job with it, packing it to the brim with comedy, illustrations, and fun context for the game's setting and story. The employee handbook's 42 pages provide a lot of flavor that, in my opinion, is well worth reading.

At TriOptimum, our employees are our most valuable commodity. We are committed to creating a positive and supportive work environment where everyone can thrive and grow. By following the policies outlined in this handbook, we can work together to spread our corporate values across the galaxy.

Thank you for your contributions and for being a part of the TriOptimum team.