Dolphin used to have a Miller Column view (https://en.wikipedia.org/wiki/Miller_columns), but it's gone now. That's a shame. It should come back. Ass an OS X refugee, column view was all I used in Finder--it was so good.
This is a duplicate of https://bugs.kde.org/show_bug.cgi?id=290747 for interest-tracking purposes.
*** This bug has been marked as a duplicate of bug 290747 ***