Lotus Improv

Lotus Improv was a spreadsheet program from Lotus Development released in 1991 for the NeXTSTEP platform 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 re-define the way a spreadsheet program should work, in order to ease the building of new spreadsheets or modifying existing ones. Whereas conventional spreadsheets used on-screen cells to store all data, formulas and notes, Improv separated these concepts apart and used the cells only for input and output data. Formulas, macros and other objects existed "outside" of the cells, which was intended to make editing much simpler and less error-prone. Additionally, Improv used named ranges for all formulas, as opposed to cell addresses.

Improv found a strong following in certain niche markets, notably financial modeling, although it was not a commercial success in comparison to mainstream products like Lotus 1-2-3 or Microsoft Excel. It was very influential within these special markets, and spawned a number of clones on different platforms, notably Lighthouse Design's Quantrix, which has since been spun off into its own company. Apple Inc.'s Numbers combines a formula and naming system similar to Improv's, but running within a conventional Excel-like spreadsheet.