Googling "History of spreadsheets" gives
http://dssresources.com/history/sshistory.html
as its first hit. There may be useful information in other hits as well.

Spreadsheets give a convenient interface for calculating and doing
what-if scenarios. As noted in the link and by other responders, it was
first contemplated in a financial setting, but the implications for all
kinds of other calculations were grasped very rapidly. It is probably
not an overstatement to say that spreadsheet applications almost single
handedly carried PCs from an electronic hobbyist's toy into a business
and subsequently household appliance.

Jerry

Trainboy85 wrote:

This is a something i need to know for an IT Assignment and this is that only
thing i don't know.