In Python, __dict__ and __dir__ are special attributes and methods that provide information about objects and classes.

1. __dict__: The __dict__ attribute is a dictionary that stores the attributes and methods of an object. Each object in Python has its own __dict__ that contains the object's namespace - a mapping of attribute names to their corresponding values. When you access an attribute of an object using dot notation (e.g., object.attribute), Python looks up the attribute in the object's __dict__.

   For example:

   class MyClass:
       def __init__(self, x):
           self.x = x
   
   obj = MyClass(42)
   print(obj.__dict__)  # Output: {'x': 42}
   

   In this example, obj.__dict__ contains the attribute x with the value 42.

2. __dir__: The __dir__ method is used to retrieve a list of valid attributes and methods that are available for an object or a class. When you call the dir() built-in function without any arguments, it internally calls the object's __dir__ method to provide a list of attributes and methods that can be accessed on that object.

   For example:

   class MyClass:
       def my_method(self):
           pass
   
   obj = MyClass()
   print(dir(obj))  
   # Output: ['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', ... 'my_method']
   

   In this example, the dir(obj) call returns a list of attributes and methods available for the obj object, including the special methods and attributes like __class__, __delattr__, __dict__, __dir__, and the custom method my_method.

In summary, __dict__ is an attribute that holds a dictionary of an object's attributes and their values, while __dir__ is a method that provides a list of valid attributes and methods for an object or class.