This book lists encyclopedia by nickname 100s

unknown mainly European Royals from ancient times

till now.

With a potted little known biography of each.

Its not a pretty picture.

Almost all come a cropper through nefarious behaviour

often barbaric or mad.

Amongst other facts we learn George 4th continued the madness

of George 3rd,

Asks was Oliver Cromwells' son gay?

etc etc & much much more.

Penguin,

Minor ding dangs to cover,

Caution much detail of torture, barbarism ,megalamaniac abuse of power etc.