Obviously, you can often find corporate history on the company's website!  The sources below will sometimes give you more detail, or a different viewpoint (i.e. not the company's viewpoint), or go back further in time.

Ok, so why would anyone need this apart from an historian?!

Well, knowing about significant events in a company's history often helps explain oddities or breaks in data about the company, or can help explain why there isn't any data!  So this page points you to some easy ways to find corporate history. 

I know that you already know how to find the company website and whatever history the company may choose to highlight in their investor section!  These sources often, or at least sometimes, offer more than that ...

And I also know that in general you probably do not want to read an entire book about the company, nor have the time to do so!  But you can -- here's how.