Thank you for choosing this book to start your PySpark adventures, I hope you are as excited as I am. When Denny Lee first told me about this new book I was delighted-one of the most important things that makes Apache Spark such a wonderful platform, is supporting both the Java/Scala/JVM worlds and Python (and more recently R) worlds. Many of the previous books for Spark have been focused on either all of the core languages, or primarily focused on JVM languages, so it's great to see PySpark get its chance to shine with a dedicated book from such experienced Spark educators. By supporting both of these different worlds, we are able to more effectively work together as Data Scientists and Data Engineers, while stealing the best ideas from each other's communities.

It has been a privilege to have the opportunity to review early versions of this book, which has only increased my excitement for the project. I've had the privilege of being at some of the same conferences and meetups and watching the authors introduce new concepts in the world of Spark to a variety of audiences (from first timers to old hands), and they've done a great job distilling their experience for this book. The experience of the authors shines through with everything from their explanations to the topics covered. Beyond simply introducing PySpark they have also taken the time to look at up and coming packages from the community, such as GraphFrames and TensorFrames.

I think the community is one of those often-overlooked components when deciding what tools to use, and Python has a great community and I'm looking forward to you joining the Python Spark community. So, enjoy your adventure; I know you are in good hands with Denny Lee and Tomek Drabas. I truly believe that by having a diverse community of Spark users we will be able to make better tools useful for everyone, so I hope to see you around at one of the conferences, meetups, or mailing lists soon :)

Holden Karau

P.S.

I owe Denny a beer; if you want to buy him a Bud Light lime (or lime-a-rita) for me I'd be much obliged (although he might not be quite as amused as I am).