using System;

using System.Collections.Generic;

using System.Linq;

using MoreLinq.Extensions;

​

public class Program

{

    public class Test {

        public int Id {get;set;}

        public string Title {get;set;}

        public Type Type {get;set;}

    }

    public enum Type {

        Kindle

    }

    public static void Main()

    {

        var ret = new List<Test> {

            new Test {

                Id = 0,

                Title = "Book A",

                Type = Type.Kindle

            },

            new Test {

                Id = 0,

                Title = "Book A",

                Type = Type.Kindle

            }

        };

        var b = ret.DistinctBy(x => new { x.Title, x.Type }).ToList();

        b.ForEach(x => Console.WriteLine(x.Title));

    }

}