diff --git a/README.md b/README.md
index 7950359..b06429a 100644
--- a/README.md
+++ b/README.md
@@ -1,163 +1,9 @@
-# acme
+# acme ![MIT license](https://img.shields.io/badge/license-MIT-blue.svg?style=flat-square)
 
-![unstable](https://img.shields.io/badge/api-unstable-orange.svg?style=flat-square)
-![MIT license](https://img.shields.io/badge/license-MIT-blue.svg?style=flat-square)
+`kelunik/acme-client` is a standalone ACME client written in PHP. ACME is the protocol that powers the [Let's Encrypt](https://letsencrypt.org) certificate authority.
 
-`kelunik/acme-client` is a standalone ACME client written in PHP.
-It's an alternative for the [official client](https://github.com/letsencrypt/letsencrypt) which is written in python.
+## Documentation
 
-> **Warning**: This software is under development. Use at your own risk.
-
-## Installation
-
-**Requirements**
-
-* PHP 5.5+
-* Composer
-
-**Instructions using the Phar**
-
-```bash
-# Go to https://github.com/kelunik/acme-client/releases/latest
-# Download the latest release archive
-
-# Run it.
-chmod +x acme-client.phar
-./acme-client.phar
-
-# Or install it globally
-mv ./acme-client.phar /usr/local/bin/acme-client
-```
-
-If you want to update, just replace the old phar with a new one.
-
-All commands require an additional `--storage` argument when using the phar. That's the path where your keys and certificates will be stored.
-On Unix you could use something like `--storage /etc/acme`.
-
-If you're using the phar, you can add a file called `acme-client.yml` next to it with the two keys `storage` and `server`.
-These values will be used as default if you don't specify them, but you can still use another server by explicitly adding it as argument.
-
-```yml
-# Sample YAML configuration:
-storage: /etc/acme
-server: letsencrypt
-```
-
-**Instructions using Composer**
-
-```bash
-# Clone repository
-git clone https://github.com/kelunik/acme-client && cd acme-client
-
-# Checkout latest release
-git checkout $(git describe --tags `git rev-list --tags --max-count=1`)
-
-# Install dependencies
-composer install --no-dev
-```
-
-## Migration from 0.1.x to 0.2.x
-
-```bash
-# Start in ./data
-cd data
-
-# Move your account key to new location:
-
-mkdir accounts
-mv account/key.pem accounts/acme-v01.api.letsencrypt.org.directory.pem
-# or accounts/acme-staging.api.letsencrypt.org.directory.pem if it's a staging key
-
-# account should now be empty or contain just a config.json, you can delete the folder then
-rm -rf account
-
-# Migrate certificates to new location:
-
-cd certs
-mkdir acme-v01.api.letsencrypt.org.directory
-
-# Move all your certificate directories
-# Repeat for all directories!
-mv example.com acme-v01.api.letsencrypt.org.directory
-# or acme-staging.api.letsencrypt.org.directory
-
-# Delete all config.json files which may exist
-find -name "config.json" | xargs rm
-
-# Update to current version
-git checkout master && git pull
-
-# Check out latest release
-git checkout $(git describe --tags `git rev-list --tags --max-count=1`)
-
-# Update dependencies
-composer update --no-dev
-
-# Reconfigure your webserver to use the new paths
-# and check (and fix) your automation commands.
-```
-
-## Usage
-
-> **Note**: This client stores all data in `./data`, be sure to backup this folder regularly.
-> It contains your account keys, domain keys and certificates.
-
-Before you can issue certificates, you have to register an account first and read and understand the terms of service of the ACME CA you're using.
-For Let's Encrypt there's a [subscriber agreement](https://letsencrypt.org/repository/) you have to accept.
-
-By using this client you agree to any agreement and any further updates by continued usage.
-You're responsible to react to updates and stop the automation if you no longer agree with the terms of service.
-
-```
-bin/acme setup -s letsencrypt --email me@example.com
-```
-
-`-s` / `--server` can either be a URI or a shortcut. Available shortcuts:
- * `letsencrypt` / `letsencrypt:production`
- * `letsencrypt:staging`
-
-After a successful registration you're able to issue certificates.
-This client assumes you have a HTTP server setup and running.
-You must have a document root setup in order to use this client.
-
-```
-bin/acme issue -s letsencrypt -d example.com:www.example.com -p /var/www/example.com
-```
-
-To revoke a certificate, you need a valid account key currently, just like for issuance.
-
-```
-bin/acme revoke --name example.com -s letsencrypt
-```
-
-For renewal, there's the `bin/acme check` subcommand.
-It exists with a non-zero exit code, if the certificate is going to expire soon.
-Default check time is 30 days, but you can use `--ttl` to customize it.
-
-You may use this as daily cron:
-
-```
-bin/acme check --name example.com --ttl 30 -s letsencrypt || bin/acme issue ...
-```
-
-You can also use a more advanced script to automatically reload the server as well.
-
-```bash
-#!/usr/bin/env bash
-
-cd /git/kelunik/acme-client
-
-bin/acme check --name example.com --ttl 30 -s letsencrypt
-
-if [ $? -eq 1 ]; then
-        bin/acme issue -d example.com:www.example.com -p /var/www -s letsencrypt
-
-        if [ $? -eq 0 ]; then
-                nginx -t -q
-
-                if [ $? -eq 0 ]; then
-                        nginx -s reload
-                fi
-        fi
-fi
-```
\ No newline at end of file
+ * [Installation](./doc/installation.md)
+ * [Usage](./doc/usage.md)
+ * [Migration guide for 0.1.x → 0.2.x](./doc/migrations/0.2.0.md)
diff --git a/doc/installation.md b/doc/installation.md
new file mode 100644
index 0000000..a102b4f
--- /dev/null
+++ b/doc/installation.md
@@ -0,0 +1,66 @@
+# Installation
+
+## Installation using Phar
+
+This is the preferred installation method for usage on a production system.
+
+### Requirements
+
+* PHP 5.5+
+
+### Instructions
+
+```bash
+# Go to https://github.com/kelunik/acme-client/releases/latest
+# Download the latest release archive.
+
+# Make it executable.
+chmod +x acme-client.phar
+
+# Run it.
+./acme-client.phar
+
+# Or install it globally.
+mv ./acme-client.phar /usr/local/bin/acme-client
+acme-client
+```
+
+If you want to update, just replace the old `.phar` with a new one.
+
+All commands require a `--storage` argument when using the Phar. That's the path where your keys and certificates will be stored.
+On Unix you could use something like `--storage /etc/acme`.
+
+You can add a file named `acme-client.yml` next to the `.phar` with the two keys `storage` and `server`.
+These values will be used as default if you don't specify them, but you can still use another server by explicitly adding it as argument.
+
+```yml
+# Sample YAML configuration.
+
+# Storage directory for certificates and keys.
+storage: /etc/acme
+
+# Server to use. Available shortcuts: letsencrypt, letsencrypt:staging
+# You can also use full URLs to the directory resource of an ACME server
+server: letsencrypt
+```
+
+## Installation using Composer
+
+If you plan to actively develop this client, you probably don't want the Phar but install the dependencies using Composer.
+
+### Requirements
+
+* PHP 5.5+
+* [Composer](https://getcomposer.org/)
+
+### Instructions
+
+```bash
+# Clone repository
+git clone https://github.com/kelunik/acme-client && cd acme-client
+
+# Install dependencies
+composer install
+```
+
+You can use `./bin/acme` as script instead of the Phar. Please note, that all data will be stored in `./data` as long as you don't provide the `--storage` argument.
diff --git a/doc/migrations/0.2.0.md b/doc/migrations/0.2.0.md
new file mode 100644
index 0000000..8a09b3a
--- /dev/null
+++ b/doc/migrations/0.2.0.md
@@ -0,0 +1,43 @@
+# Migration from 0.1.x to 0.2.x
+
+If you used this client before `0.2.0`, you have a different directory structure than the current one. If you want to upgrade, but keep all your data, here's a migration guide.
+
+```bash
+# Start in ./data
+cd data
+
+# Move your account key to new location:
+
+mkdir accounts
+mv account/key.pem accounts/acme-v01.api.letsencrypt.org.directory.pem
+# or accounts/acme-staging.api.letsencrypt.org.directory.pem if it's a staging key
+
+# account should now be empty or contain just a config.json, you can delete the folder then
+rm -rf account
+
+# Migrate certificates to new location:
+
+cd certs
+mkdir acme-v01.api.letsencrypt.org.directory
+
+# Move all your certificate directories
+# Repeat for all directories!
+mv example.com acme-v01.api.letsencrypt.org.directory
+# or acme-staging.api.letsencrypt.org.directory
+
+# Delete all config.json files which may exist
+find -name "config.json" | xargs rm
+
+# Update to current version
+# Alternatively have a look at the new installation instructions and use the Phar
+git checkout master && git pull
+
+# Check out latest release
+git checkout $(git describe --tags `git rev-list --tags --max-count=1`)
+
+# Update dependencies
+composer update --no-dev
+
+# Reconfigure your webserver to use the new paths
+# and check (and fix) your automation commands.
+```
diff --git a/doc/usage.md b/doc/usage.md
new file mode 100644
index 0000000..abb8b61
--- /dev/null
+++ b/doc/usage.md
@@ -0,0 +1,79 @@
+# Usage
+
+**The client stores all data in `./data` if you're using the Composer installation method, otherwise in the directory you configured. Be sure to backup this folder regularly. It contains your account keys, domain keys and certificates.**
+
+Before you can issue certificates, you have to register an account first and read and understand the terms of service of the ACME CA you're using.
+For the Let's Encrypt certificate authority, there's a [subscriber agreement](https://letsencrypt.org/repository/) you have to accept.
+
+By using this client you agree to any agreement and any further updates by continued usage.
+You're responsible to react to updates and stop the automation if you no longer agree with the terms of service.
+
+These usage instructions assume you have installed the client globally as a Phar. If you are using the Phar, but don't have it globally, replace `acme-client` with the location to your Phar.
+
+If you're using the client with Composer, replace `acme-client` with `bin/acme`. You have to specify the server with `-s` / `--server`, because there's currently no config file support for this installation method.
+
+## Register an Account
+
+```
+acme-client setup --email me@example.com
+```
+
+After a successful registration you're able to issue certificates.
+This client assumes you have a HTTP server setup and running.
+You must have a document root setup in order to use this client.
+
+## Issue a Certificate
+
+```
+acme-client issue -d example.com:www.example.com -p /var/www/example.com
+```
+
+You can separate multiple domains (`-d`) with `,`, `:` or `;`. You can separate multiple document roots (`-p`) with your system's path separator:
+ * Colon (`:`) for Unix
+ * Semicolon (`;`) for Windows
+
+If you specify less paths than domains, the last one will be used for the remaining domains.
+
+Please note that Let's Encrypt has rate limits. Currently it's five certificates per domain per seven days. If you combine multiple subdomains in a single certificate, they count as just one certificate. If you just want to test things out, you can use their staging server, which has way higher rate limits by appending `--s letsencrypt:staging`.
+
+## Revoke a Certificate
+
+To revoke a certificate, you need a valid account key, just like for issuance.
+
+```
+acme-client revoke --name example.com
+```
+
+`--name` is the common name of the certificate that you want to revoke.
+
+## Renewing a Certificate
+
+For renewal, there's the `acme-client check` subcommand.
+It exists with a non-zero exit code, if the certificate is going to expire soon.
+Default check time is 30 days, but you can use `--ttl` to customize it.
+
+You may use this as daily cron:
+
+```
+acme-client check --name example.com || acme-client issue ...
+```
+
+You can also use a more advanced script to automatically reload the server as well. For this example we assume you're using Nginx. Something similar should work for Apache.
+
+```bash
+#!/usr/bin/env bash
+
+acme-client check --name example.com --ttl 30
+
+if [ $? -eq 1 ]; then
+        acme-client issue -d example.com:www.example.com -p /var/www
+
+        if [ $? -eq 0 ]; then
+                nginx -t -q
+
+                if [ $? -eq 0 ]; then
+                        nginx -s reload
+                fi
+        fi
+fi
+```