Years ago someone asked me to define what a nation is and the best I could come up with was that it's a group of people that have agreed that they belong to the same nation, and it was the only explanation that actually made sense. While arguing with bunch of people on the internet ("can't use a thing to define itself"), someone actually agreed with me and recommended this book.
Like the title says, the author considers nations imagined communities. He tries to explain how nationalism came to existence, It's a snowball that rolled for a long time, I chose some of important milestones:
"print capitalism" got the ball rolling (you can see that he is a Marxist, and that it influenced his theories), the printing press gave the people a new way to turn profit, and seeking to sell books to as big of a consumer base as possible, they started printing in vernacular instead of Latin, the lingua franca of the educated aristocratic class, vernacular soon also becomes the language of religious service and people start forming kinship on linguistic instead of religious basis, and national consciousness starts to form. But the Chinese invented the printing press hundreds of years before Euros, how come they didn't also come up with nationalism? They lacked capitalism as the second important ingredient. This sounds kinda flimsy to me, but fine. Next significant step was colonialism, and the resentment of Creols in Americas (Creols is the term he uses for whites born in colonies, and he includes the founding fathers there too) over the unequal treatment and lack of political agency, causing them to rebel and form separate identities. According to him, nationalism wasn't created in Europe, it originated in the Americas, and was then pirated across the world.
The final step was making nationalism official & state approved, since it came from the people (educated middle class), not from the top. With the loss of divine right, the royal houses (in most cases of German origin and not even speaking the languages of the people they ruled), had to adapt to the masses and adopt new national identities (Hanovers became Windsors).
He goes on to provide examples how nationalism developed in different countries, why some sooner, others later . Also at the end of the book, comments how he regrets the book not being published earlier in Yugoslavia, it may have defused the jingoistic tensions and stopped the war

oh the cute naivety of the academics
here's some stuff to amuse you
@fleacollerindustry
@minty
Marx didn't have the balls to define nationalism
on the phenomenon of glorifying the unknown soldier and nationalism being closer to a religion than to an ideology:
Nothing justifies glorious Japanese imperialism as much as Marxism:
