Lotus Improv
Lotus Improv running on NeXTSTEP showing Improv's interface to multidimensional data
Developer	Lotus Development
Initial release	1991; 35 years ago (1991)
Operating system	NeXTSTEP, Windows 3.1
Type	spreadsheet

Lotus Improv is a discontinued spreadsheet program from Lotus Development released in 1991 for the NeXTSTEP platform^[1] and then for Windows 3.1 in 1993. Development was put on hiatus in 1994 after slow sales on the Windows platform, and officially ended in April 1996 after Lotus was purchased by IBM.

Improv was an attempt to redefine the way a spreadsheet program should work, to make it easier to build new spreadsheets and to modify existing ones. Conventional spreadsheets used on-screen cells to store all data, formulas, and notes. Improv separated these concepts and used the cells only for input and output data. Formulas, macros and other objects existed outside the cells, to simplify editing and reduce errors. Improv used named ranges for all formulas, as opposed to cell addresses.

Although not a commercial success in comparison to mainstream products like Lotus 1-2-3 or Microsoft Excel, Improv found a strong following in certain niche markets, notably financial modeling. It was very influential within these special markets, and spawned a number of clones on different platforms, notably Lighthouse Design's Quantrix.

Apple Inc.'s Numbers combines a formula and naming system similar to Improv's, but running within a conventional spreadsheet.