The WinDASI software performs financial and economic analyses of agricultural and rural activities in a multi-period context. It provides a framework to organise input-output data, unit prices and investment by activity and time period. It allows flexible aggregations of different activities and performs most of the calculations required in benefit-cost analysis. It computes : total inputs and outputs in physical terms, flows of costs and benefits, incremental flows of costs and benefits, present values and net present values, internal rates of return, switching values, cost benefit ratios and sensitivity tests. WinDASI is particularly suitable for investment project analysis. In addition, in cases of multi-period activities such as perennial crops or livestock, WinDASI could also be used to perform analyses of farming systems, commodity chains and build Policy Analysis Matrices. This publication consists of a CD containing the WinDASI software and its manual. The manual includes instructions on how to install and operate the software as well as four step-by-step exercises to help the user practise.