[bhl]

A good book to learn about how a cell "suddenly decides to build an eyeball" might be: The Gene: An Intimate History. Its a good overview of genetics. It had an interesting chapter about insect embryo research where experiments were done to learn about cells becoming specific body parts... and what happens if you move cells around at various stages.

[cuban leaf]

Thanks, I will definitely check it out! It’s really hard to find anything discussing that particular topic.