diff --git a/examples/deribit_book.py b/examples/deribit_book.py
new file mode 100644
index 0000000..d98c838
--- /dev/null
+++ b/examples/deribit_book.py
@@ -0,0 +1,80 @@
+#!/usr/bin/env python
+import asyncio
+import json
+import logging
+from ssc2ce import Deribit
+from ssc2ce.deribit.l2_book import L2Book
+
+conn = Deribit()
+
+pending = {}
+books = {}
+
+logging.basicConfig(format='%(asctime)s %(name)s %(funcName)s %(levelname)s %(message)s', level=logging.INFO)
+logger = logging.getLogger("deribit-book")
+
+
+async def handle_instruments(data: dict):
+    request_id = data["id"]
+    del pending[request_id]
+    print(json.dumps(data))
+    if not pending:
+        await subscribe_books(list(books.keys()))
+
+
+async def handle_currencies(data: dict):
+    for currency in data["result"]:
+        symbol = currency["currency"]
+        instrument = symbol+"-PERPETUAL"
+        book = L2Book(instrument)
+        book.top_bid = [0., 0.]
+        book.top_ask = [0., 0.]
+        books[instrument] = book
+        request_id = await conn.get_instruments(symbol, kind="future", callback=handle_instruments)
+        pending[request_id] = symbol
+
+
+async def get_currencies():
+    await conn.get_currencies(handle_currencies)
+
+
+async def subscribe_books(instruments: list):
+    await conn.send_public(request={
+        "method": "public/subscribe",
+        "params": {
+            "channels": [f"book.{i}.raw" for i in instruments]
+        }
+    })
+
+
+async def handle_subscription(data):
+    method = data.get("method")
+    if method and method == "subscription":
+        params = data["params"]
+        channel = params["channel"]
+        if channel.startswith("book."):
+            params_data = params["data"]
+            instrument = params_data["instrument_name"]
+            book: L2Book = books[instrument]
+            if "prev_change_id" in params_data:
+                book.handle_update(params_data)
+            else:
+                book.handle_snapshot(params_data)
+
+            if book.top_ask[0] != book.asks[0][0] or book.top_bid[0] != book.bids[0][0]:
+                book.top_ask = book.asks[0].copy()
+                book.top_bid = book.bids[0].copy()
+                print(f"{instrument} bid:{book.top_bid[0]} ask:{book.top_ask[0]}")
+        else:
+            print("Unknown channel", json.dumps(data))
+
+
+conn.on_connect_ws = get_currencies
+conn.method_routes += [("subscription", handle_subscription)]
+
+loop = asyncio.get_event_loop()
+
+try:
+    loop.run_until_complete(conn.run_receiver())
+except KeyboardInterrupt:
+    print("Application closed by KeyboardInterrupt.")
diff --git a/examples/deribit_private.py b/examples/deribit_private.py
index e5debc6..f561c33 100644
--- a/examples/deribit_private.py
+++ b/examples/deribit_private.py
@@ -7,7 +7,7 @@
 from uuid import uuid4
 from typing import Pattern
 from dotenv import load_dotenv
-from ssc2ce.deribit import Deribit, AuthType
+from ssc2ce import Deribit, AuthType
 
 
 class MyApp:
diff --git a/requirements.txt b/requirements.txt
index 4c61d9d..cd2dd54 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,3 +2,4 @@ aiohttp
 python-dotenv
 twine
 wheel
+sortedcontainers
diff --git a/setup.py b/setup.py
index 9f3db89..502c274 100644
--- a/setup.py
+++ b/setup.py
@@ -7,7 +7,7 @@
 
 setuptools.setup(
     name='ssc2ce',
-    version="0.9.0",
+    version="0.10.0",
     author='Oleg Nedbaylo',
     author_email='olned64@gmail.com',
     description='A Set of Simple Connectors for access To Cryptocurrency Exchanges',
diff --git a/ssc2ce/__init__.py b/ssc2ce/__init__.py
index 7c52420..509f820 100644
--- a/ssc2ce/__init__.py
+++ b/ssc2ce/__init__.py
@@ -1,4 +1,5 @@
 from .deribit import Deribit
+from .common import AuthType
 from .bitfinex import Bitfinex
 
 from pkg_resources import get_distribution, DistributionNotFound
diff --git a/ssc2ce/bitfinex/__init__.py b/ssc2ce/bitfinex/__init__.py
new file mode 100644
index 0000000..5901f8a
--- /dev/null
+++ b/ssc2ce/bitfinex/__init__.py
@@ -0,0 +1 @@
+from .bitfinex import Bitfinex
diff --git a/ssc2ce/bitfinex.py b/ssc2ce/bitfinex/bitfinex.py
similarity index 98%
rename from ssc2ce/bitfinex.py
rename to ssc2ce/bitfinex/bitfinex.py
index da1eb70..05cd32b 100644
--- a/ssc2ce/bitfinex.py
+++ b/ssc2ce/bitfinex/bitfinex.py
@@ -3,8 +3,8 @@
 
 import aiohttp
 
-from .session import SessionWrapper
-from .utils import resolve_route
+from ssc2ce.common.session import SessionWrapper
+from ssc2ce.common.utils import resolve_route
 
 from enum import IntEnum
 
diff --git a/ssc2ce/common/__init__.py b/ssc2ce/common/__init__.py
new file mode 100644
index 0000000..ae5724c
--- /dev/null
+++ b/ssc2ce/common/__init__.py
@@ -0,0 +1 @@
+from .auth_type import AuthType
\ No newline at end of file
diff --git a/ssc2ce/common/abstract_l2_book.py b/ssc2ce/common/abstract_l2_book.py
new file mode 100644
index 0000000..7535508
--- /dev/null
+++ b/ssc2ce/common/abstract_l2_book.py
@@ -0,0 +1,44 @@
+from sortedcontainers import SortedKeyList
+from abc import abstractmethod, ABC
+from .l2_book_side import L2BookSide, SortedKeyList
+
+
+class AbstractL2Book(ABC):
+    """
+
+    """
+
+    def __init__(self, instrument: str):
+        """
+
+        :param instrument:
+        """
+        self.instrument = instrument
+        self._bids = L2BookSide(is_bids=True)
+        self._asks = L2BookSide(is_bids=False)
+
+    @abstractmethod
+    def handle_snapshot(self, message: dict) -> None:
+        """
+
+        :param message:
+        :return:
+        """
+        pass
+
+    @abstractmethod
+    def handle_update(self, message: dict) -> None:
+        """
+
+        :param message:
+        :return:
+        """
+        pass
+
+    @property
+    def bids(self):
+        return self._bids.data
+
+    @property
+    def asks(self):
+        return self._asks.data
diff --git a/ssc2ce/common.py b/ssc2ce/common/auth_type.py
similarity index 100%
rename from ssc2ce/common.py
rename to ssc2ce/common/auth_type.py
diff --git a/ssc2ce/common/exceptions.py b/ssc2ce/common/exceptions.py
new file mode 100644
index 0000000..0702d9d
--- /dev/null
+++ b/ssc2ce/common/exceptions.py
@@ -0,0 +1,8 @@
+class Ssc2ceError(Exception):
+    """Base class for errors."""
+
+
+class BrokenOrderBook(Exception):
+    def __init__(self, instrument, prev_change_id, change_id):
+        self.instrument = instrument
+        self.message = f"instrument:{self.instrument} expected:{change_id} != received:{prev_change_id}"
diff --git a/ssc2ce/common/l2_book_side.py b/ssc2ce/common/l2_book_side.py
new file mode 100644
index 0000000..14874dd
--- /dev/null
+++ b/ssc2ce/common/l2_book_side.py
@@ -0,0 +1,63 @@
+from sortedcontainers import SortedKeyList
+
+VERY_SMALL_NUMBER = 1e-11
+
+
+class L2BookSide:
+
+    def __init__(self, is_bids: bool):
+        if is_bids:
+            self.data = SortedKeyList(key=lambda val: -val[0])
+        else:
+            self.data = SortedKeyList(key=lambda val: val[0])
+        self.is_bids = is_bids
+        self.time = None
+        self.changes = list()
+
+    def fill(self, source):
+        self.data.clear()
+        for item in source:
+            self.add(item)
+
+    def add(self, item):
+        price = float(item[0])
+        size = float(item[1])
+        self.changes.append([price, size, size])
+        self.data.add([price, size])
+
+    def update(self, price: float, size: float):
+        key = -price if self.is_bids else price
+        i = self.data.bisect_key_left(key)
+
+        if 0 <= i < len(self.data):
+            value = self.data[i]
+        else:
+            if size <= VERY_SMALL_NUMBER:
+                self.changes.append([price, size, 0.0])
+                return False
+
+            self.data.add([price, size])
+            self.changes.append([price, size, size])
+            return True
+
+        if size <= VERY_SMALL_NUMBER:
+            if value[0] == price:
+                old_size = self.data[i][1]
+                self.data.discard(value)
+                self.changes.append([price, size, -old_size])
+                return True
+            else:
+                self.changes.append([price, size, 0.0])
+                return False
+
+        if value[0] == price:
+            old_size = self.data[i][1]
+            self.data[i][1] = size
+            self.changes.append([price, size, size - old_size])
+        else:
+            self.data.add([price, size])
+            self.changes.append([price, size, size])
+        return True
+
+    def delete(self, price: float):
+        return self.update(price, 0.0)
diff --git a/ssc2ce/session.py b/ssc2ce/common/session.py
similarity index 100%
rename from ssc2ce/session.py
rename to ssc2ce/common/session.py
diff --git a/ssc2ce/utils.py b/ssc2ce/common/utils.py
similarity index 100%
rename from ssc2ce/utils.py
rename to ssc2ce/common/utils.py
diff --git a/ssc2ce/deribit/__init__.py b/ssc2ce/deribit/__init__.py
new file mode 100644
index 0000000..1b0ffbb
--- /dev/null
+++ b/ssc2ce/deribit/__init__.py
@@ -0,0 +1 @@
+from .deribit import Deribit
\ No newline at end of file
diff --git a/ssc2ce/deribit.py b/ssc2ce/deribit/deribit.py
similarity index 97%
rename from ssc2ce/deribit.py
rename to ssc2ce/deribit/deribit.py
index 7d24c06..99e2e7e 100644
--- a/ssc2ce/deribit.py
+++ b/ssc2ce/deribit/deribit.py
@@ -3,10 +3,10 @@
 
 import aiohttp
 
-from .exceptions import Ssc2ceError
-from .common import AuthType
-from .session import SessionWrapper
-from .utils import resolve_route, hide_secret, IntId
+from ssc2ce.common.exceptions import Ssc2ceError
+from ssc2ce.common import AuthType
+from ssc2ce.common.session import SessionWrapper
+from ssc2ce.common.utils import resolve_route, hide_secret, IntId
 
 
 class Deribit(SessionWrapper):
@@ -325,7 +325,7 @@ async def get_currencies(self, callback=None):
         """
         return await self.send_public(request=dict(method="public/get_currencies", params={}), callback=callback)
 
-    async def get_instruments(self, currency: str, kind: str = None, callback=None) -> int:
+    async def get_instruments(self, currency: str, kind: str = None, expired: bool = False, callback=None) -> int:
         """
         Send a request for a list available trading instruments
         :param currency: The currency symbol: BTC or ETH
@@ -335,10 +335,11 @@ async def get_instruments(self, currency: str, kind: str = None, callback=None)
         """
         request = {"method": "public/get_instruments",
                    "params": {
-                       "currency": currency
+                       "currency": currency,
+                       "expired": expired
                    }}
         if kind:
-            request["kind"] = kind
+            request["params"]["kind"] = kind
 
         return await self.send_public(request=request, callback=callback)
 
diff --git a/ssc2ce/deribit/l2_book.py b/ssc2ce/deribit/l2_book.py
new file mode 100644
index 0000000..428a4ac
--- /dev/null
+++ b/ssc2ce/deribit/l2_book.py
@@ -0,0 +1,67 @@
+import logging
+from ssc2ce.common.abstract_l2_book import AbstractL2Book
+from collections import deque
+
+from ssc2ce.common.exceptions import BrokenOrderBook
+
+
+class L2Book(AbstractL2Book):
+    change_id = None
+    timestamp = None
+    logger = logging.getLogger(__name__)
+
+    def __init__(self, instrument: str):
+        """
+
+        :param instrument:
+        """
+        AbstractL2Book.__init__(self, instrument)
+
+    def handle_snapshot(self, message: dict) -> None:
+        """
+
+        :param message:
+        :return:
+        """
+        self.asks.clear()
+        self.bids.clear()
+
+        self.change_id = message["change_id"]
+        self.timestamp = message["timestamp"]
+        for i in message['bids']:
+            self.bids.add([i[1], i[2]])
+
+        for i in message['asks']:
+            self.asks.add([i[1], i[2]])
+
+    def handle_update(self, message: dict) -> None:
+        """
+
+        :param message:
+        :return:
+        """
+        prev_change_id = message["prev_change_id"]
+        if prev_change_id != self.change_id:
+            raise BrokenOrderBook(self.instrument, prev_change_id, self.change_id)
+
+        self.change_id = message["change_id"]
+        self.timestamp = message["timestamp"]
+        for change in message['bids']:
+            if change[0] == 'new':
+                self._bids.add(change[1:])
+            elif change[0] == 'delete':
+                self._bids.delete(change[1])
+            else:
+                self._bids.update(price=change[1], size=change[2])
+
+        for change in message['asks']:
+            if change[0] == 'new':
+                self._asks.add(change[1:])
+            elif change[0] == 'delete':
+                self._asks.delete(change[1])
+            else:
+                self._asks.update(price=change[1], size=change[2])
+
+
+def create_l2_order_book(instrument: str) -> AbstractL2Book:
+    return L2Book(instrument)
diff --git a/ssc2ce/exceptions.py b/ssc2ce/exceptions.py
deleted file mode 100644
index d1d2c8d..0000000
--- a/ssc2ce/exceptions.py
+++ /dev/null
@@ -1,2 +0,0 @@
-class Ssc2ceError(Exception):
-    """Base class for errors."""