Andrew Brown discusses why some defects slip unnoticed to testers, explaining how to notice or pay attention to an event or object. In ongoing software development, our core work is changing code. Jessica Kerr argues that by building changeable software on top of existing, well-understood components, and by improving delivery automations, teams will get better at their core work of delivering value and “changing reality”. Jibin Liu presents one of his projects at eBay where the team used RL to improve crawling of targeted web pages, starting from the basics of RL, then to why and how to use it to power web crawling. Peter Pito explores how to create a set of heuristics underpinned by Agile principles and practices that can be used to create a delivery foundation. Successful long-term approaches to production ownership and DevOps require cultural change in the form of production excellence. Teams are more sustainable if they have well-defined measurements of reliability, the capability to debug new problems, a culture that fosters spreading knowledge, and a proactive approach to mitigating risk. Yevgeni Litvin describes how Petastorm facilitates tighter integration be...