This chapter provides a basic introduction to single molecule fluorescence detection. A brief introduction provides the motivation for detecting fluorescence at the single molecule level and seeks to explain why single molecule spectroscopy has gained so much popularity, especially in the biosciences. A brief history of single molecule detection will discuss how single molecule sensitivity was achieved historically and how it has progressed since then. Details of the typical instrumentation are provided with an emphasis on reproducibility for newcomers to this field. We then discuss sample preparation for single molecule experiments, we will detail what evidence argues for the detection of single fluorescent molecules, and we will end with a brief outlook into the future of this field.