I need a tool to access my email inbox via some convenient interface. For example, I need to get the timestamps of letters from some address. I need that data to build some mailing statistics.
What can I use to do that? Maybe there is an API in Thunderbird or something like that. I work under Windows.
Thank you in advance.
EDIT: Maybe I can do that with some Python library?
Your best bet is to use a programming language that has a simple IMAP library which you can use to connect to your account. Then you will have to write a script that can do your statistics. 
Since you asked for an API I assume that you know how to use a scripting language like PHP, Python or Ruby which all have an IMAP library available.
Mail inbox analyzer