Well, most American schools traditionally only taught about early Western European history. So, the history of Poland, Ukraine, Russia and the Baltics gets missed. Then there is the issue of ethnic bias of many North American history profs. Many Jewish profs focus on the Holocaust, while de-emphasizing other very important matters, and in Canada the profs tend to have a pro-Ukrainian bias, and Ukraine was neither a state nor a recognized ethnicity before WWI. The leading Polish historian in the U.S., Jan Marek Chodkiewicz, teaches at The Institute of World Politics, which although affiliated with Boston University, is not itself a university. Chodkiewicz is well known for his work
Intermarium: The Land between the Black and Baltic Seas . Because he has a different perspective than most other North American history profs, he is not well received by them.