You must be the reason I get a captcha to read a single book.

If they were smart, they would throw up some torrents themselves. One for each category, one for the whole library. Make use of the people who would leave up their p2p client to spread the load. Everybody wins!

Could you share your scripts, for those or us with lesser scripting skills

Putting out a script runnable by everybody might put too much strain on Springer's servers (and their generosity). I'll give some steps that the motivated can follow instead.

1. Extract a list of all a.btn links from the OP page (382 total).

2. Issue a HEAD request and follow redirects for each link to get the actual page URL (I used curl for this).

3. The page URL contains the book ID. Compare a sample URL's format with its PDF and ePub links. Each page URL can be easily munged into both (sed here).

4. The download pages are captcha-protected, but there's a <noscript> escape hatch in the source. Find it and pass the appropriate data in a POST request to the final file URLs (wget).

A torrent could share the load perhaps

Someone released this a bit ago: https://github.com/alexgand/springer_free_books

Looks like this script is not working anymore. I wanted to try the script when I saw this couple of months back in twitter. And in the process downloaded the whole catalogue.

Perhaps we could all seed your torrent?

I don't torrent, and it's silly to violate copyright on something they're literally offering for free...

Bear in mind that while they're letting you download it for free, Springer doesn't permit redistribution.