Data is not delete it give this error ->Cannot convert value of type `array` to integer error

1 
<?php 

namespace App\Controller;

use App\Controller\AppController;
use App\View\AppView ;
use Cake\View\Helper;

class BookController extends AppController {

	public function initialize()
	{
		parent::initialize() ;		
		$this->loadModel("Books");
		$this->viewBuilder()->layout("booklayout");
		$this->loadComponent('Csrf');
	

	}


	public function index()
	{
	
			$books = $this->Books->find("all" ,["order"=>["book_id"=>"desc"]]);
			$this->set("title" , "Book List");
			$this->set("books" , $books);

	}
public function delete($id){
		$this->autoRender = false ; 
		$book = $this->Books->get($id);

		$this->Books->delete($book);
		$this->Flash->set('book has been deleted' ,["element"=>"book_success"]);
		$this->redirect(["action"=>"index"]);

}
2 
index.ctp file 

<div class="panel panel-primary">
  <div class="panel-heading">Book List

<?php echo $this->Html->link(
"Create Book" ,
"/Book/create/" ,
[
					"class"=>"btn btn-info pull-right" ,
					"style"=>"margin-top :-6px"
				]
				);
				?>

  </div>
  <div class="panel-body">
<table class="table">
    <thead>
      <tr>
        <th>Sr. No</th>
        <th>Book Name</th>
         <th>Author</th>
        <th>Email Address</th>
         <th>Action</th>
      </tr>
    </thead>
    <tbody>
      <?php 
      $count = 1;
        foreach($books as $key=>$book){  ?>

      <tr>
        <td><?= $count++;?></td>
        <td><?= $book->name; ?></td>
        <td><?= $book->author; ?></td>
        <td><?= $book->email ;?></td>
        
        <td>
        <?php 
			echo $this->Html->link(
				"Edit" ,
				"/book/edit/".$book->book_id ,
				[
					"class"=>"btn btn-info"
				]
				);

echo $this->Html->link(
				"delete" ,
				"/book/delete/".$book->book_id ,
				[
					"class"=>"btn btn-danger"
				]
				);
        ?>
    
        </td>
      </tr>
      <?php }?>
     
    </tbody>
  </table>
  </div>
</div>
3

Where exactly does that error occur? The code you have shown here looks like it should work, so I wonder if it’s in an event handler somewhere.