Collect 75 Total Lore Pages -
1. Start a Game With A Large Map, and Hard or Brutal Difficulty.
2. Click on the Laptop to Download Objectives.
3. If there is AT LEAST 2 Lore Pages in your map, Run it until you find the Lore Page.
(If Not See Step - 6)
4. Don't Open the Inner Tomb,
That makes 1 of out 2 Lore Pages inaccessible BUT5. Takes anywhere from 1 minute to 20 minutes to search the ruins. Collect the Lore Page (And/or Artifact) and
6. Run back out to the entrance, Put Any Collected On The Table, And Close the Hatch On The Jeep.
7. Repeat Steps 1-6.
Takes a while but its not as big of a grind as you think, some maps have up to 4 Lore Pages - so you can get 3 and boogy.
Good Luck!
Edit For v1.0 - Lore Pages No Longer Float Or Glow, And There Are More Lore Pages On Lower Difficulties.
Video Guide: