In the battle for dominance of the e-book reader market, Amazon with kindle 2 was ahead of Sony with its Reader Digital Book. Kindle 2 had the biggest number of recent titles available, but thanks to a deal with Google, sony had a huge number of out-of-copyright titles. What are the sources of network externalities in this market? Will e-book readers become a winner-takes-all market? Why has Amazon been able to gain a lead over Sony (and Samsung)? What can Sony do to fight back?.