Are the two Jaycee Dugard books a series?

[Dan]

I'm still trying to get a handle on nonfiction series and what constitutes and doesn't constitute a series. I think these two books constitue a series since they have topic/characters in common? But with nonfiction is difficult to be sure.

https://www.goodreads.com/book/show/1...
https://www.goodreads.com/book/show/2...

[Liralen]

I'd say yes, because the second book is a direct follow-up to the first one. The rules are definitely not as well defined with nonfiction, though.