As fans of the Harry Potter universe already know, Newt Scamander is the author of the “real” Fantastic Beasts And Where To Find Them that all Hogwarts students read during their formative years, so Redmayne will actually read the book as his silver screen character.
To put this into layperson’s terms: the upcoming Harry Potter book is NOT an adaptation of anything that audiences have seen on the silver screen; it is an in-universe piece of literature.
Fantastic Beasts And Where To Find Them was first released back in 2001, and is being re-released following the motion picture of the same name.
The book was originally released as a children’s companion piece to the novel series, alongside fellow “textbook” Quidditch Through the Ages.