That is why you place it at the top and try to make it as captivating as possible.
It is the first thing everyone who checks out your document looks at. You use it to introduce your project by highlighting each part of your business document. In one sense, the executive summary is simple, but it takes work to write, considering its sensitivity. It sums up the whole report, so anyone can get a quick overview by reading that alone.
This is only a part of other documents such as business plans, proposals, etc.