Improv was also a product from Lotus Software. Steve Jobs originally hailed it as the killer app for his NeXT computer or, as it later became, his NeXTStep operating system.
Lotus Improv was a 'next-generation spreadsheet', designed to make manipulation and analysis of multi-dimensional data really easy.
And if that's what you do with spreadsheets, then Lotus Improv is definitely the product for you.
When IBM decided to port it across to the Microsoft Windows 3.0, they even had the Microsoft Excel development team qualing in their boots. So they hurriedly added a facility called pivot tables into the product in an attempt to compete. (for details, go and read the JoelOnSoftware website).
As it turned out, most people use Excel for simple sums, and sorting single flat tables of information into alphabetical or numerical order.
Lotus Improv was complete overkill for this, and was not the Excel-killer that Lotus had hoped for. Consequently, they withdrew it from sale within about 12 months of the Windows 3.0 launch.
And this is unfortunate, because it was one of the best apps ever for manipulating multi-dimensional data - never bettered, often mourned.