What is the subject in the following sentence? This is the book I wanted

This is the book I wanted.

In this sentence, is 'this' the formal subject and 'book' the real Subject?


"this" is the subject, "the book I wanted" is the subject complement. "book" is merely a noun within the phrase that constitutes the complement.

If you invert the sentence to

The book I wanted is this one.

then "The book I wanted" becomes the subject.

They both have very similar meanings, but the emphasis is different.