“Your” as a third person possessive pronoun. Is that a thing?

Question

Your book suggests that animals have thought processes, emotions, and social connections that are as important to them as they are to us

This is a snippet of this article I found on internet and the “your” at the beginning refers to Carl Safina's book Beyond words: How animals think and feel. Is this a real thing in formal English or a more informal thing? Or could it even be an error by the author of the article?

Answer 1

The article is, by implication, an interview with the author, with the journalist's questions in bold type.

Speaking from Stony Brook University... he explains...

The first question begins with the reference to 'your book'.