Chock full of Machiavellian politics and sibling rivalry, the Amber series tells of a universe full of parallel worlds progressing along a hierarchy from most organized (Amber) to least (The Courts of Chaos). In the middle are a myriad of other worlds collectively called Shadow, including our own Earth. Closest to Amber is Avalon, the mythical world of lords and knights, and the primary world that Amber does trade with.
Guns of Avalon, the second book in Roger Zelazny's critically acclaimed Chronicles of Amber, tells the continuing tale of Corwin's quest to recover the throne from his brother Eric. Having escaped Eric's prison at Amber, Corwin flees to the nearby world of Avalon in an attempt to mount a force to regain the throne.
The title refers to Corwin's attempts to ignite gunpowder in Amber -- due to a quirk in the makeup of the universe, guns cannot traditionally be fired in Amber. Corwin solves this problem by using a substance that does not ignite as gunpowder anywhere else, but which works in Amber. During this quest, Corwin meets a mysterious and beautiful girl, Dara, who claims to be his brother Benedict's granddaughter, who proves to be important later.
Intriguing and engrossing, by the end of this book it will be a hardship not to immediately pick up the third book, Sign of the Unicorn, and begin reading.