A book is on the table / There is a book on the table

[wotcha]

1) A book is on the table.

2) There is a book on the table.

3) My book is on the table.

4) There is my book on the table.

Are they all grammatically correct?

[billmcd]

1) A book is on the table. OK

2) There is a book on the table.OK

3) My book is on the table.OK

4) There is my book on the table. If you are referring to the location of the book, it would be better to say, "My book is there, on the table.

Are they all grammatically correct?

b.

[birdeen's call]

Wotcha, this is also correct:

"What is on the table?"
"On the table is my book."

[5jj]

There is a book on the table.
My book is on the table.

Of all the possibilities, these are the two we'd be most likely to say/hear.