I’m not actually sure what the first alternate history was. Some argue Livy wrote one in 9 BC. However, the earliest ones dealt with the immediate result of something different happening in history. Usually, what if the other side won a war.
The Wheels of If, from what I can tell, was one of the first that explored the idea of long term, global effect. While set in the 1940s, the key changes took place centuries earlier and we see much more massive changes. Since then, literally hundreds of works have taken a similar tact.
The Wheels of If also uses the ideas of multi-verses with everyone having variations of themselves in other universes although not in most of them. The title comes from the idea of all of them going over one click, their minds ending up in their bodies in the next universe over.
Allister Park, a New York lawyer, gets pulled out of his own body into a series of alternate versions of himself, until he ends in the body of a Bishop in a world where the Roman Catholic Church is much weaker, Southern Europe is held by Muslims and the Americas were settled much earlier so the native population was able to fight back better.
Oh and the body swapping was all done as political machinations by one of the political opponents of the bishop. Which seems like a crazy amount of work when less metaphysical methods are out there.
However, Park’s New York chutzpah and political savvy let him turn the tables and take control of the situation, even creating a second identity as his old name Allister Park. His efforts to get back to his own timeline upset the political landscape enough that a three-front war ends up starting in North America.
That particular escalation is a little abrupt but de Camp handles it well enough that you can buy into it, which is an impressive bit of writing.
By modern standards, Park is an anti-hero. He is downright Machiavellian in his actions, which are pretty much completely self-serving. He uses women pretty much like disposable playthings. (In fact, there are no female characters of note in the story) And he admires the racist, corrupt political boss who got him into the mess because he knows how to party.
However, de Camp keeps us on Park’s side because he’s so gosh darn clever, his enemies are worse and he ultimately makes the world a better place, even if it’s unintentional, although Park is happy with the results.
Still, I suspect Park was more conventionally heroic when the story first was written.
What is fascinating about the Wheels of If is that is a seminal work that changed the way folks approached alternate history but de Camp uses it to serve the story. Park’s adventures are the point. Alternate history is just the backdrop. de Camp changed the genre but it was a side effect of telling the story.
And maybe that’s why the Wheels of If still holds up so well. A little dated but still engaging.