{
    PersonDetails: [
        {
            Book: "10 ",
            FirstName: "Delbert",
            LastName: "Hinson",
            Remarks: null
        },
        {
            Book: "5 ",
            FirstName: "GUY",
            LastName: "HINSON",
            Remarks: null
        },
        {
            Book: "13 ",
            FirstName: "JAMES",
            LastName: "HINSON",
            Remarks: null
        },
        {
            Book: "7 ",
            FirstName: "JOHN, SR",
            LastName: "HINSON",
            Remarks: null
        }
    ]
}

namespace VAPerson
{

    public class PersonDetail
    {
        public string Book { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public object Remarks { get; set; }
    }

    public class RootObject
    {
        public List<PersonDetail> PersonDetails { get; set; }
    }

}

protected void Page_Load(object sender, EventArgs e)
    {
        string lastName = "hinson";
        var url = string.Format(baseUrl, lastName);
        var syncClient = new WebClient();
        var content = syncClient.DownloadString(url);

        var personDetail = JsonConvert.DeserializeObject<RootObject>(content);

        GridView1.DataSource = personDetail;
        GridView1.DataBind();

    }

GridView1.DataSource = personDetail.PersonDetails;