diff --git a/README.md b/README.md
index 64a466a..b048040 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,20 @@
+# Sisyphus: Intelligent Junk Mail Handler
+As we all know too well, many mails we receive are undesired for various
+reasons. Sometimes, we just do not want to be part of a scam, sometimes we
+really prefer no to have this latest joke mail sent by our beloved friends --
+even though we are happy to exchange serious messages with them.
+
+**Sisyphus** is a junk mail handler of the latest generation. It has the
+following features:
+
+* requires zero configuration, neither on the server nor on the client
+* works with any MTA and any client
+* learns about your preferences based on all messages in your inbox and your
+  junk folder
+* can handle multiple mail accounts with independant junk mail preferences
+* is fully daemonized, runs smoothly in the background
+* requires minimal resources by using the HyperLogLog algorithm to store learned mails
+
 [![Build Status](https://travis-ci.org/carlostrub/sisyphus.svg?branch=master)](https://travis-ci.org/carlostrub/sisyphus)
 [![Go Report Card](https://goreportcard.com/badge/github.com/carlostrub/sisyphus)](https://goreportcard.com/report/github.com/carlostrub/sisyphus)
 [![GoDoc](https://godoc.org/github.com/carlostrub/sisyphus?status.svg)](https://godoc.org/github.com/carlostrub/sisyphus)
@@ -5,7 +22,57 @@
 [![Codebeat](https://codebeat.co/badges/64615809-e3c4-4267-a049-eaec20ad63b5)](https://codebeat.co/projects/github-com-carlostrub-sisyphus-master)
 [![Coverage](https://gocover.io/_badge/github.com/carlostrub/sisyphus?0 "Coverage")](http://gocover.io/github.com/carlostrub/sisyphus)
 
-# sisyphus
-Intelligent, easy to configure Spam cleaner
+## How it works
+Sisyphus analyzes each mail in the inbox and the junk folder and uses its
+subject and text to improve the learning algorithm. Whenever a new mail arrives
+in the `Maildir/new` directory, Sisyphus classifies this mail based on its
+content. Junk mails are then moved automatically to the `Maildir/.Junk`
+directory, while good mails are left untouched.
+
+Technically, Sisyphus applies a classic [Bayesian Update
+algorithm](https://en.wikipedia.org/wiki/Bayesian_inference) to classify mails.
+However, in contrast to many traditional junk mail filters, classification is
+based on all mails ever received. This includes mails that are classified by
+the user as junk by moving them manually into the junk folder, or mails that
+have been correctly classified by Sisyphus previously. This is only possible
+with limited resources by applying the [HyperLogLog
+algorithm](https://en.wikipedia.org/wiki/HyperLogLog) to store the learned
+mails.
+
+The learned information is stored in a local database called `sisyphus.db`
+which is located in each `Maildir` directory.
+
+## Install
+Sisyphus can be installed by downloading the released [binary
+package.](https://github.com/carlostrub/sisyphus/releases)
+
+To build from source, you can
+1. Clone this repository into `$GOPATH/src/github.com/carlostrub/sisyphus` and
+   change directory into it
+2. Run `make build`
+
+This will leave you with `./sisyphus` in the `sisyphus` directory, which you
+can put in your `$PATH`. (You can also take a look at `make install` to install
+for you.)
+
+## Usage
+Sisyphus help can be started by running
+```
+# sisyphus help
+```
+
+To start sisyphus, do
+```
+# sisyphus --maildir PATHTOMAILDIR  run
+```
+
+To run it in the background, do
+```
+# sisyphus --maildir PATHTOMAILDIR  start
+```
+
+See the help for more details.
 
-This software is work in progress. Wait for more to come.
+## License
+Sisyphus is licensed under the 3-Clause BSD license. See the LICENSE file for
+detailed information.