Here is DatasetAndApply.nb. I have also attached \Dataset_Tutorial.nb , which is another attempt at describing what Dataset does.

The current presentation of Dataset[] as a mere display convenience ignores most of what Dataset can do. It is excellent at rapid processing of large amounts of data, in some cases at least processing data that List[] could not fit into memory.

Attachments:

DatasetAndApply.nb

DatasetTutorial.nb

We are trying to locate the attachment file DatasetAndApply.nb, but in meantime if @Bill Lewis currently has it, could you please attach it to a new comment?

The trick is that Dataset[] is Apply[], in a way. It is a computational structure that applies functions to Associations in a highly unusual (but pretty much regular) way. See the Dataset[] documentation and work through the example. Takes a long time, but the notation and system is sufficiently unusual that there isn't any other way.

First, though, see attached file DatasetAndApply.nb for examples. It gives a hint of what is going on.

Attachments: