The coordination and manipulation of complex machines.
While a prospector concentrates on finding raw materials in the vastness of space, engineers study how to make something out of them. They also take a number of science courses that allow them to study and copy blueprints (which are a necessity in all production), produce goods and use cybernetic implants to increase their capabilities. Being a successful manufacturer takes a considerable effort in the beginning, as the more complex products take a while to produce. Engineering is an excellent foundation to build a successful space ship career on. Being tech-savvy allows a captain to be more than just the driver of his ship - he becomes the ship's master. In the hi-tech world of EVE, being comfortable around complex machines can mean the difference between life and death.