The topic of time travel provides tantalizing conundrums to consider for STEM experts and sci-fi creators alike. Most scientists and mathematicians agree that time travel by humans is probably impossible, yet they have not been able to offer conclusive proof. This book describes how the very nature of time remains a fascinating and complex subject, whether viewed from the perspective of Einstein's relativity or the nanoscale realm of quantum physics. Readers will recognize notable fictional works in literature, film, and television in which time travel serves as a useful plot device as well as a means of examining human history and contemporary social issues.