Welcome to this post, in which we’ll be taking a trip through the wild and bumpy ride that has been Vitamin D & sunlight research over the past few decades, and what it might mean for COVID-19. As with my previous post, before any non-specialist attempts to write something on COVID-19, we should wonder: are any actual experts already writing on this, and if not, why not. Enough badly informed stuff has already been published by amateurs that before posting we should be certain we are actually being helpful.