The Evolution of Venus

Venus has an extraordinary atmosphere, it's extraordinarily complicated and that is a big part of the puzzle about understanding that. Is it the hottest planet as I've seen it described hotter than Mercury which as far as I know is much closer to the sun? And there are many other differences between Venus and Earth and just the amount of energy they receive from the sun because we also know that Venus has a relatively little magnetic field. Also, Venus doesn't really have a strong magnetic field. We don't really understand why.