Tintin in America, the third book in the series, continues the early theme of Tintin being a crime fighting superhero who just happens to be a journalist too (something which was toned down in subsequent books, though lets face it Tintin was seldom ever seen doing anything that remotely resembled being a journalist).
Tintin arrives in the USA to clean up Chicago and is almost immediately thrown into peril. The story is a break-neck series of adventures as Tintin battles Al Capone and has other adventures across the US.
Thus there isn't the intricate plot that marks out the later books, this one is more a series of events that just happen to take place in the same country however its still a good read. There is some great satire here such as the fancy metropolis that pops up overnight after the discovery of oil and social comment on the bad treatment of Native Americans (though they do look like they come straight out a Western movie).
It is full of stereotypes but these reflected the America that existed (and still does to an extent) in the minds of Europeans in the pre-war period. Their image of America largely came from the movies. Thus America is a land of skyscrapers, canyons, mobsters, Red Indians, cowboys and lynching! Quite a few movie references were thrown in by Herge.
The artwork is not up to quite the standard of the later books but still good. Its worth reading, you miss the ensemble that was built up in later books, but enough of the magic is still there.