So far, more or less, each book corresponds to a season of the Starz series. Season 1 is Outlander, season 2 is Dragonfly in Amber, and so on. Season 7, part 2 is airing right now, and one of the last episodes of this season is named " Written in My Heart's Own Blood ," which implies that we might start to get season 8 plots.

Blood of My Blood showrunner Matthew B. Roberts explains the extent of Diana Gabaldon's involvement in the prequel series.

Outlander: Blood of my Blood’ isn’t based on a specific book like the original Starz series, but author Diana Gabaldon has written a prequel novella in the past, and she’s written two episodes for the new show.