It is easy to create seemingly impossible scenarios in special relativity by playing on the counterintuitive nature of observer-dependent time. These scenarios are usually called paradoxes, because they seem to be impossible. Yet there is nothing paradoxical about them!

The best way to resolve these paradoxes is to draw a good spacetime diagram. This requires careful reading of the problem, making sure always to associate the given information with a particular reference frame. A single spacetime diagram suffices to determine what all observers see. It is nevertheless instructive to draw separate spacetime diagrams for each observer, making sure that they all agree.

In this chapter, we discuss the two most famous paradoxes in special relativity, the Pole and Barn Paradox and the Twin Paradox. We also briefly discuss the more subtle aspects of flying manhole covers.