That's like asking, "What is the value of my car?" The answer would depend upon the specific book, its condition, and how rare it is.
The copyright date is the year the text was completed. It may or may not be the same as the publication date.
1967- copyright renewed 1995
The copyright date for "Eragon" by Christopher Paolini is 2002.
The copyright date of the original book is July 24th, 1954The copyright date of the movie is December 19th, 2001The copyright date of the video game is September 24th, 2002
2006.
1998
1971.
2008.
1990.
1987.
2002.
1988.