Lars Marius Garshol has worked as a consultant, product developer, and open source developer for two decades. He added Unicode support to the Opera web browser, edited a number of ISO standards, and developed the query language tolog. Later, he worked as an enterprise architect and an R&D developer. He is the developer of Duke, an open source tool for identifying near-duplicate database records. He wrote Definitive XML Application Development, published in 2002. Currently he is a software engineer at Schibsted Products & Technology in Oslo, Norway. He's working on a book on Norwegian farmhouse ale.

Alexey Grigorev is an experienced software developer and data scientist with five years of professional experience. In his day-to-day job, he actively uses R and Python for data cleaning, data analysis, and modeling. He believes that testing is not only an integral part of software development, but it is also very useful for building machine learning models.