The goal of this article is to provide an updated and in-depth review of some of the most exciting and important developments in the processing and properties of carbon nanotubes. Nanotubes can be formed in various structures using several different processing methods. The synthesis methods used to produce specific kinds of nanotubes are discussed and a comparison is made between the methods used by researchers and industrial producers. This is followed by an overview and discussion of what makes carbon nanotubes interesting to so many: their mechanical, chemical, electrical, thermal, and optical properties. The article ends with a discussion of the future outlook for the study of carbon nanotubes.