A rare typescript by Antoine de Saint-Exupéry The Little Princecontaining numerous handwritten corrections by the French author and described by booksellers as a “literary treasure”, will soon be put on sale for $1.25 million.

Bound under a worn black cover, the French typewritten text of The Little Prince was made in New York during the author’s exile from Nazi-occupied France, just before he left to serve in the Free French Air Force fighting the occupation.

The other two copies, out of the three existing, are at the French National Library and at the Harry Ransom Center, in the American state of Texas.

The typescript features what is believed to be the first written appearance of one of the book’s most famous lines: “Only with the heart can one see aright; the essential is invisible to the eye.