Read Tweets from your timeline.
See who you follow, and follow new people.
Update your profile.
Post Tweets for you.
Seems a little excessive. Edit: Link to screenshot - http://imgur.com/a/rAO0d
The website that asks for that stuff is open-source[1], though, so you can take a look at what it does (just send out a single tweet).
If you still feel uneasy about granting me access to tweet through your account, that's perfectly understandable, and I have two options that may work for you:
- Revoke access right after you authorize the app. The tweet will still be sent out, and you will still keep your access to the HTML chapters. Since I don't get access to your DMs, there's no harm nor potential harm done.
- Just read the book on GitHub[2]. It isn't as pretty as the HTML version, but it works well enough and alleviates your security concerns.
Personally, I'm more likely to give attention to someone's organic Tweet than autogenerated marketing because it implies that the book is good at being a book. I don't really care about books that are good at social media and SEO.
In purely product terms, company's that care more about their brand than my 'brand' don't garner a high level of trust.
Good luck.
Considering that I'm giving five books away entirely for free, asking for a single tweet isn't that high of a bar, to be honest. I don't mind a few people being annoyed by it, particularly because I can point those people to GitHub and be done with it :)