25 $$+$$ Years of Query Processing - From a Single, Stored Data Set to Big Data (and Beyond)

From the late 1970s, the database research community has devoted huge efforts in devising more and more effective and efficient solutions for processing queries against data. In this chapter, we retrace some of challenges that have been faced in the last 25 years to enable data to be effectively and efficiently queried and how the notions of queries and query processing themselves have evolved during these five lusters.