Plugging or mentioning? Anyway I didn't know about this book and now I do so said comment isn't pointless. No need for the unpleasant tone.
It's certainly unrelated to the article, and the OP didn't understand why they received downvotes, so I believe my explanation was sufficient.
And it is absolutely related to the article. The very concept and terminology of "gap" is the first thing Rosling critiques in Factfulness, as a faulty way of thinking that misleads us and keeps us from seeing the truth about the state of the world.