I'm working on the basis that there's not much point in putting ET-type books together unless a fair few people - i.e. 1000 and upwards - are going to read them. Ideally some media interest would be a good thing too.

Giving stuff away for free only works online. I know someone who has given away >100,000 copies of a book about the music business. It's a good book, and it's been very influential as a free download.

As a paper project, he might have sold 10-100 copies.

Online, people find you. In physical print, you need to find them, which seems to be rather harder.

If you want to print for friends+family+a few left over, that's usually called vanity publishing, and is a different animal again.

Getting even a small print run of 500 is a major operation. 500 books is a big slab of wood pulp, and  takes up a lot of space. In hardback it's heavy enough to significantly stress a domestic floor.

You really wouldn't want it in your home. Which is why publishers usually pay distributors to handle the physical logistics of moving that much dead wood around.

You can certainly self-publish at that scale, and people do - sometimes successfully, sometimes not.

But it needs a bit of forethought to make sure you can still get into your home after you've had the books delivered.

If we want to sell books it seems much easier to upload them as PDFs, set up a paypal account with voluntary donations and/or a fixed price, and point people at a print on demand service if (and only if) they want a hard copy.