está escribiendo un libro

is writing a book

→ estar

phrase Rare #28,282

is writing a book Present continuous form. In the examples, it describes someone currently working on a book.

SP: Mi hermana está escribiendo un libro sobre su viaje.

EN: My sister is writing a book about her trip.

The cat is writing a book.

He is writing a book this year.

He is also writing a book.

He is writing a book.

He is writing a book now.

He's writing a new book, and I see a lot of physical media here, right?

— Doña Clara (2016)

Tom is writing a book, isn't he?