There are 12 Earths in the novel...in this article, I am going to tell you a little bit about them. If you want to know more, I'm afraid you are going to have to buy the book.
A. A world of wonders where magic was so powerful and abundant that technology, except in some rudimentary forms, never toke hold. Atlantis never sank and many empires extinct to us still flourish.
B. A world much like this one where the unthinkable happened: World War 3 broke out and the survivors were trapped in a nuclear winter.
C. Three Earths so alike, that the visitors are almost indistinguishable from one another.
D. A history where the monarchies did not fail due to better leadership and the absence of such people as Lenin and Robespierre.
E. Another history, much like ours, were Germany got the Bomb first and, using an untested prototype, devastated London. Through fear, they were allowed to do as they wished in Europe. World War Two never happened...although a secret war of assassination and sabotage went on, led by a weekend League of Nations.
F. Probably this reality.
...and so on..
One common link between the characters from these different worlds is their ancestors originated in Ireland...some stayed, others at some time immigrated.
