Wonder Books did not publish any books featuring Harvey characters in 1964. They resumed in 1965 with book 850 “Casper in Ghostland”. They published book 855 “Casper and Wendy Adventures” in 1969, then ceased publishing in 1977. Rick Beckham contributed both of these last books:

View the exhibits:

Casper in Ghostland Wonder Book

Casper and Wendy Adventures Wonder Book