There is good evidence of the use of fire 800,000 years ago so one could 
add fire as a source of light at night.

Steve

Craig Miles wrote:
> For those that have read this book (I have but don't recall mention of
> this). It talks about how even small amounts of light at night can disrupt
> hormones etc. Now not all paleo peoples would have slept in the dark
> recesses of a cave - so how does moonlight fit into this? Is it as a light
> source too weak to disrupt the hormones?
>
> Regards,
> Craig,
>