In the vast number of discussions, academic lectures, and books/papers regarding nuclear radiation, I have always learned about the "three" basic types of nuclear radiation - alpha, beta, and gamma.
But recently, I watched Dr. Don Lincoln's (Fermilab) video about types of radiation - he discusses the four types of such radiation (the above three plus neutron radiation).
While there's no denying that neutron radiation is equally important as the other three in any research or discussion of nuclear radiation, it seems less mentioned by a large factor. My generalization here is made by personal experience reading and learning about nuclear physics from my atomic-age youth to the present.
Why is this?
Does it have something to do with how the other three are present in naturally-occurring elements (e.g. carbon-14, potassium-40, uranium ores, etc.) whereas neutron radiation is caused by the decay involving one of the other three?
I dare say that neutron radiation is perhaps the nastiest of them all when it comes to biological effects.
Please note that I have already reviewed the below Physics SE questions (and their answers):