Can someone provide a full description of how a quarterwave vertical antenna
with radials works? Length of radials is also a quarterwave.

I find that many books give a good description of antennas like the Yagi,
and then suddenly become very vague when describing the quarterwave
vertical. Books
refer to image theory where an image of the radiating element is produced by
the radials, and show a spear shape going into the ground. Some say the
radials are the other half of a dipole.

What difference does it make if the radials are in free space or in the
ground? Some articles claim that the radials tend not radiate because they
cancel out, while other other articles claim that the radials simulate a
ground plane and reflect the radio wave. Can you explain this contradiction?

The vertical element is usually called the radiating element. How well do
the radials radiate? The same magnitude of current flows into the vertical
element as the radials, although the current into the radials is split.

A normal ground plane is a large sheet of metal that reflects the radio wave
emitted by the radiating element. If there are four radials, each a
quarterwave long, do the radials form a ground plane? Or is there too much
of a gap for them to form a ground plane?

If the radials are disconnected and taken away, with the vertical
quarterwave element still connected to centre conductor, do I still have a
radiating element? What happens to the SWR?