When I open the daily newspaper as part of my morning routine, I often see lengthy descriptions of conflicts between people on borders, properties, or liberties. Today's news is often forgotten a few days later. But when one opens ancient texts that have appealed to a broad audience over a longer period of time, such as the Bible, what does one often find in the opening chapter?... a discussion of how the constituents of the Universe (including light, stars and life) were created. Although humans are often occupied with mundane problems, they are curious about the big picture. As citizens of the Universe, we cannot help but wonder how the first sources of light formed, how life came to existence, and whether we are alone as intelligent beings in this vast space. As astronomers in the twenty first century, we are uniquely positioned to answer these big questions with scientific instruments and a quantitative methodology. In this pedagogical review, intended for students preparing to specialize in cosmology, I will describe current ideas about one of these topics: the appearance of the first sources of light and their influence on the surrounding Universe. This topic is one of the most active frontiers in present-day cosmology. As such it is an excellent area for a PhD thesis of a graduate student interested in cosmology. I will therefore highlight the unsolved questions in this field as much as the bits we understand.