Python exposes a lot of built-in functionality through its **standard library**.

The standard library is a huge collection of all sort of utilities, ranging from math utilities to debugging to creating graphical user interfaces.

You can find the full list of standard library modules here: https://docs.python.org/3/library/index.html

Some of the important modules are:

`math`

for math utilities`re`

for regular expressions`json`

to work with JSON`datetime`

to work with dates`sqlite3`

to use SQLite`os`

for Operating System utilities`random`

for random number generation`statistics`

for statistics utilities`requests`

to perform HTTP network requests`http`

to create HTTP servers`urllib`

to manage URLs

Let’s introduce how to *use* a module of the standard library. You already know how to use modules you create, importing from other files in the program folder.

Well that’s the same with modules provided by the standard library:

```
import math
math.sqrt(4) # 2.0
```

or

```
from math import sqrt
sqrt(4) # 2.0
```

We’ll soon explore the most important modules individually to understand what we can do with them.