I started writing this book after I came back from the 2018 RStudio Conference in early February, and finished the first draft in early May. This may sound fast for a 300-page book. The main reason I was able to finish it quickly was that I worked full-time on this book for three months. My employer, RStudio, has always respected my personal interests and allowed me to focus on projects that I choose by myself. More importantly, I have been taught several lessons on how to become a professional software engineer since I joined RStudio as a fresh PhD, although the initial journey turned out to be painful. It is a great blessing for me to work in this company.

The other reason for my speed was that JJ and Garrett had already prepared a lot of materials that I could adapt for this book. They had also been offering suggestions as I worked on the manuscript. In addition, Michael Harper contributed the initial drafts of Chapters 12, 13, 15, 17, and 18. I would definitely not be able to finish this book so quickly without their help.

The most challenging thing to do when writing a book is to find large blocks of uninterrupted time. This is just so hard. Both others and myself could interrupt me. I do not consider my willpower to be strong: I read random articles, click on the endless links on Wikipedia, look at random Twitter messages, watch people fight on meaningless topics online, reply to emails all the time as if I were able to reach “Inbox Zero”, and write random blog posts from time to time. The two most important people in terms of helping keep me on track are Tareef Kawaf (President of RStudio), to whom I report my progress on the weekly basis, and Xu Qin, from whom I really learned the importance of making plans on a daily basis (although I still fail to do so sometimes). For interruptions from other people, it is impossible to isolate myself from the outside world, so I’d like to thank those who did not email me or ask me questions in the past few months and used public channels instead as I suggested. I also thank those who did not get mad at me when my responses were extremely slow or even none. I appreciate all your understanding and patience. Besides, several users have started helping me answer GitHub and Stack Overflow questions related to R packages that I maintain, which is even better! These users include Marcel Schilling, Xianying Tan, Christophe Dervieux, and Garrick Aden-Buie, just to name a few. As someone who works from home, apparently I would not even have ten minutes of uninterrupted time if I do not send the little ones to daycare, so I want to thank all teachers at Small Miracles for freeing my daytime.

There have been a large number of contributors to the R Markdown ecosystem. More than 60 people have contributed to the core package, rmarkdown. Several authors have created their own R Markdown extensions, as introduced in Part III of this book. Contributing ideas is no less helpful than contributing code. We have gotten numerous inspirations and ideas from the R community via various channels (GitHub issues, Stack Overflow questions, and private conversations, etc.). As a small example, Jared Lander, author of the book R for Everyone, does not meet me often, but every time he chats with me, I will get something valuable to work on. “How about writing books with R Markdown?” he asked me at the 2014 Strata conference in New York. Then we invented bookdown in 2016. “I really need fullscreen background images in ioslides. Look, Yihui, here are my ugly JavaScript hacks,” he showed me on the shuttle to dinner at the 2017 RStudio Conference. A year later, background images were officially supported in ioslides presentations.

As I mentioned previously, R Markdown is standing on the shoulders of the giant, Pandoc. I’m always amazed by how fast John MacFarlane, the main author of Pandoc, responds to my GitHub issues. It is hard to imagine a person dealing with 5000 GitHub issues over the years while maintaining the excellent open-source package and driving the Markdown standards forward. We should all be grateful to John and contributors of Pandoc.

As I was working on the draft of this book, I received a lot of helpful reviews from these reviewers: John Gillett (University of Wisconsin), Rose Hartman (UnderstandingData), Amelia McNamara (Smith College), Ariel Muldoon (Oregon State University), Yixuan Qiu (Purdue University), Benjamin Soltoff (University of Chicago), David Whitney (University of Washington), and Jon Katz (independent data analyst). Tareef Kawaf (RStudio) also volunteered to read the manuscript and provided many helpful comments. Aaron Simumba, Peter Baumgartner, and Daijiang Li volunteered to carefully correct many of my typos. In particular, Aaron has been such a big helper with my writing (not limited to only this book) and sometimes I have to compete with him in correcting my typos!

There are many colleagues at RStudio whom I want to thank for making it so convenient and even enjoyable to author R Markdown documents, especially the RStudio IDE team including J.J. Allaire, Kevin Ushey, Jonathan McPherson, and many others.

Personally I often feel motivated by members of the R community. My own willpower is weak, but I can gain a lot of power from this amazing community. Overall the community is very encouraging, and sometimes even fun, which makes me enjoy my job. For example, I do not think you can often use the picture of a professor for fun in your software, but the “desiccated baseR-er” Karl Broman is an exception (see Section 7.3.6), as he allowed me to use a mysteriously happy picture of him.

Lastly, I want to thank my editor, John Kimmel, for his continued help with my fourth book. I think I have said enough about him and his team at Chapman & Hall in my previous books. The publishing experience has always been so smooth. I just wonder if it would be possible someday that our meticulous copy-editor, Suzanne Lassandro, would fail to identify more than 30 issues for me to correct in my first draft. Probably not. Let’s see.

Yihui Xie
Elkhorn, Nebraska