I published The DevOps 2.1 Toolkit: Docker Swarm on LeanPub early. I think that only around 20% was written when it went public. That allowed you to get early access to the material, and me to get your feedback. The result is fantastic. Many send me their notes, reported bugs, proposed suggestions for improvements, recommended tools and processes that should be explored, and so on.
It would be tempting to take the whole credit for the book but that would untrue. This book is the result of teamwork between the author (me) and many of the readers (you). It proves that lean publishing works and that we can apply agile principles when writing a book. There was no fixed scope and decisions were not made in advance. I would work on a chapter and deliver it when it's finished (sprint). You would review it and send your notes and comments that would allow me to improve it (sprint review). We had a daily exchange of emails, chats, and Disqus messages (daily standups). We did short iterations that allowed us to learn from the mistakes and improve.
Dear readers, you made this book great!
One sticks from the crowd. Tim Condit provided help that was beyond anything I could expect. He sent me his suggestions, told me about bugs, and corrected my "Tarzan" English. If you started reading the book early (before it was finished), you might have been annoyed with some weird sentences that clearly showed that English is not my primary language. Tim fixed that. He forked the repository with the book, proofread it, and made a vast number of changes to all the chapters. There were days when I would wake up confident that I will make significant progress on a new chapter. That enthusiasm would last only until I check my emails and see that Tim made another round of pull requests. I had to spend hours reviewing the changes he made only to realize that they are all perfect. Tim, I owe you my eternal gratitude for helping me make this book excellent.