I don't have the handbook, and I don't want to spoil the ending for myself, but does the book tell you what happens at the end of the movie essentially? Did it ruin it for you?
No.
It just says, "if you ever encounter beings from another dimension do as Indy did and get the heck out of there!"
I honestly have no idea how the movie ends exactly, and I don't wanna know until 5/22.