Eascards,
Here is what you have to do:
1 Set following mapping: http://prntscr.com/4hjbhq/direct
2 On select change - set "bookid" with selected item value. http://prntscr.com/4hj8c4/direct
3 In list/query service mapping link "bookid" to where parameter: http://prntscr.com/4hj8rd/direct
4 Click Edit js and paste following code: http://prntscr.com/4hja0r/direct
pre
var whereObject = {"Book": value};
return JSON.stringify(whereObject);
/pre
I've fixed this. Currently it should work.
But note you have strange link in your DB by book name. "Book" stores name currently. But it good way to store there "_id" instead.
Regards.