Excel is the leading spreadsheet both in its widespread distribution and in its computational features. In scientific research, spreadsheets are often used to organize and plot experimental results for reports and papers. Spreadsheets are also much-used tools in teaching some of the more quantitative aspects of science. This guidebook is different from the majority of existing Excel books in that it emphasizes the design of solutions to unique problems rather than simply the mechanics of spreadsheet use. Its focus is on the use of Excel to analyze numerical experimental data usually encountered in the physical sciences. The core of the book discusses the two primary approaches to scientific data analysis, least squares and Fourier transformation. Other cases in which experiments must be compared with the results of numerical simulations are also briefly discussed. Macros are presented as examples that readers can modify for their own purposes. The text is illustrated throughout with practical examples.