Examining eye movement through the use of eye tracking technology provides us with copious information across a variety of human processes. The advent of static, mobile, and virtual reality (VR) based eye trackers provides flexibility in studying eye movement under an array of conditions. This chapter explores the use and application of these eye tracking devices; diving into the suitability of each with respect to study design, data collection, data quality, and data analysis. We will also identify key visual behavior measures that can be assessed using eye tracking methodology and what these measures tell us. Lastly, we will examine the use of different eye trackers in relevant case studies.