How to access property values of objects in a list [duplicate]

I am using a code like the following:

let books = {       
1: {"author": "Chinua Achebe","title": "Things Fall Apart", "reviews": {} },       
2: {"author": "Samuel Beckett","title": "Molloy, Malone Dies, The Unnamable, the trilogy", "reviews": {} } 
}

booklist = Object.values(books); 
let the_book = booklist[book_index]; 

book_index is set from the isbn:

public_access.get('/review/:isbn',function (req, res) {
   let book_index = parseInt(req.params.isbn);
   book_index -=1;
   let the_book = booklist[book_index];
   console.log(the_book)        Returns one key/value pair based on the value of isbn
});
 

I have tried different ways of accessing individual key/value pairs within the_book and nothing has worked so far. I cannot find the correct syntax for it.

I checked and confirmed that the_book is properly initialized and has values.