public static void Main()
        {
            Configuration.Default.AddApiKey("api_key", "YOUR_API_KEY");

            var cryptoApi = new CryptoApi();
            var levels    = 50;       // int? | The number of prices/levels to return on each side. For example, the max of 50 levels will return up to 50 bid prices and 50 ask prices. (optional)
            var pair      = "btcusd"; // string | Return the order book summary for the given Crypto Currency Pair. (optional)
            var exchange  = "gemini"; // string | Return the order book summary for a Crypto Currency on the given Crypto Exchange. (optional)
            var currency  = "BTC";    // string | Return the order book summary for the given Crypto Currency. (optional)

            try
            {
                ApiResponseCryptoBook  result      = cryptoApi.GetCryptoBookSummary(levels, pair, exchange, currency);
                List <CryptoBookEntry> crypto_bids = result.Bids;
                List <CryptoBookEntry> crypto_asks = result.Asks;

                CryptoPairSummary crypto_pair = result.Pair;
                Console.WriteLine("Crypto Currency Pair: " + crypto_pair.Name);

                CryptoExchangeSummary crypto_exchange = result.Exchange;
                Console.WriteLine("Crypto Exchange: " + crypto_exchange.Name);

                Console.WriteLine();
                Console.WriteLine("----------------- BIDS -----------------");

                crypto_bids.ForEach(delegate(CryptoBookEntry bid)
                {
                    Console.WriteLine();
                    Console.WriteLine("Price: " + bid.Price);
                    Console.WriteLine("Size:  " + bid.Size);
                });

                Console.WriteLine();
                Console.WriteLine("----------------- ASKS -----------------");

                crypto_asks.ForEach(delegate(CryptoBookEntry ask)
                {
                    Console.WriteLine();
                    Console.WriteLine("Price: " + ask.Price);
                    Console.WriteLine("Size:  " + ask.Size);
                });
            }
            catch (Exception e)
            {
                Debug.Print("Exception when calling CryptoApi.GetCryptoBookSummary: " + e.Message);
            }
        }