ReactでforEeachのエラー

Uncaught TypeError: this.props.books.forEach is not a function

var BookTable = React.createClass({
    render: function() {
        var rows = [];
        this.props.books.forEach(function(book) { // ← ここでエラー
            rows.push(<BookTableRow key={book.id} book={book} handleEditClickPanel={this.props.handleEditClickPanel}  />);
        }.bind(this));
        return (
            <table>
                <thead>
                    <tr>
                        <th>Title</th>
                        <th>Category</th>
                        <th>Edit</th>
                    </tr>
                </thead>
                <tbody>{rows}</tbody>
            </table>
        );
    }
});
````

[http://js.studio-kingdom.com/react/guides/working_with_the_browser:title]

kriskowal's es5-shim の es5-shim.js？？