This is the 4249th most frequent Japanese word.
何処
"何処" means "where."
In this sentence, '何処' is used to ask about the location of the book.
この本は何処にありますか？
Where is this book located?
Here, '何処' is used to inquire about the desired destination.
何処へ行きたいのですか？
Where do you want to go?
In this usage, '何処' relates to the starting point or origin of the subject's journey.