Sergio van Pul is a game designer and artist interested in making interactive media entertainment. He has built games and interactive applications using Flash ActionScript. He has also worked on web designs and stylesheets, using a basic text/script editor to write raw HTML and CSS, as well as using the Drupal CMS to assemble a website. He is also familiar with visual editing tools such as Photoshop and Première.

Sergio has worked as a freelance designer and programmer on a variety of projects, many of which involved interaction and education. During this time, he met people from Scratch Web Foundation, a Dutch organization that promotes digital design and programming knowledge in primary education.

Sergio started using Scratch to teach children about programming and game design. Occasionally, he also uses Scratch as a quick and easy prototyping tool to test game interaction concepts. He likes experimenting with the program and building tutorials, examples, and complete game projects. Some of his material was printed and tested during workshop sessions for Scratch Web Foundation. This book is his first official publication.

Jessica Chiang is a senior software engineer, online educator, and technology enthusiast.

She has worked with a wide range of interesting and cutting-edge technologies including nuclear detector and unmanned aircraft-control system. Not only an inquisitive learner, she also loves to teach in class as well as online through her website (shallwelearn.com) and YouTube channel (http://www.youtube.com/user/kookoodoll).

Jessica has self-published an e-book titled Shall We Learn Scratch Programming: E for Everyone. This book has been requested by many schools to supplement their computer science and education curriculum; one such school is Jessica's alma mater, the University of California, San Diego.