They’ve been around the whole time and humans have been fighting them, but since the industrial revolution and the introduction of the automobile their activity has been increasing exponentially. There’s a few times where the book touches briefly on points in our real history, but adds the complication of dragons. i.e. African theatre of WW2 + dragons harassing supply lines.

I should clarify that the setting is modern day, not WW2 though.

The dragons seem to be mostly euro as opposed to oriental, but even then they don’t seem to be completely like european style dragons. Some of the smaller dragons are not much larger than a human from what I can gather. Most of the visual description seems to be in the cover art, which leaves a lot open to imagination.

Consider this excerpt:
‘Next was Draconis siligoinis, the smallest dragon native to Canada. It was fast enough to catch a car, in theory, but it was also pretty stupid. It got its name because it liked to hide in corn fields, which it did at all times of the year, including when the corn was not high enough to conceal it. It was also stupid enough that sometimes it couldn’t tell corn from beans, making it easier to track. If you were attacked by a siligoinis, the key was to get off the road, leave your car, and hide.

The context is that the narrator is talking about safely driving in rural Ontario and knowing how to survive dragon attacks by different species of dragons. The humour in the book tends to be pretty tongue in cheek about dragon slaying, even when talking about practical things like properly reclaiming a dragon’s corpse to minimize pollution after a slaying.