When it did the quick show of all of his books in the box, it looked like a lot of them were sci-fi. Didn’t Cecil refer to them as being travel guides in season 1? I thought Nolan was writing about all the places he’s been able to fly to on Earth.
Spoilers:
It is to help with defeating them.
Spoiler tags? > ! spoiler here with no spaces ! <
The second half of season 2 will explain the books. If you want spoilers, read at your risk:
!The books are stories of Nolan’s tales as a Viltrumite soldier, where he specifically points out things he discovered that have the capacity to actually hurt and/or kill Viltrumites. The implication is for Mark to try to find means to defend himself against the Viltrumites coming for Earth. We’ll eventually see all that he wrote about Season 3 or 4.!<
Haven’t read the comics, so this is a genuine guess. But i think his books are undercover tails of Viltrumite Empires and the intricate details about it and how Mark can protect Earth and defeat the Viltrumite empire as well as the rules and culture of Viltrum.