This is a series of quests you get after speaking to Madame Beauvoir early in the game. She wants you to find items from Old Earth to add to her collection and there are 10 of these side areas in the game. This will take until the end of the game to complete as there are Historian quest areas all the way through the last zone. Just look for the quest marker on your mini map as you explore each zone. Difficulty varies depending on World Tier so if you are having trouble just lower the difficulty or return later.
If you talk with Jakub to take the truck to a new location you will be able to see the Historian book icon on zones that still have an available Historian quest which is helpful if you are trying to find one you missed. Note that these are not complete until you return and give the item to Madame Beauvoir.