Comment by keypusher

I've always been particularly confused by the contract clauses which specify that all work of the employee during their time at the company is property of the company itself. Does this mean that if I develop some completely unrelated software in my spare time while working as a programmer at a large company, that the software I created at home also belongs to my employer? What if I was to write a book during that same time? Is anyone aware of legal battles fought over this type of contract clause? It seems fairly prevalent in the industry today.