Lawrence Barr Crowell 
Can Star Systems Be Explored?: The Physics Of Star Probes [PDF ebook] 
The Physics of Star Probes

This book is an exposition of classical mechanics and relativity that addresses the question of whether it is possible to send probes to extrasolar systems. It examines largely well-understood physics to consider the possibility of exploring the nearby interstellar environment in a similar fashion to how the solar system has been explored. As such, this book is both a semipopularization of basic physics and an informal study of a likely future technological development. An auxilliary text on basic physics for students and laypersons as well as an illustration of the problems with interstellar exploration, this book is a must-read.