There are multiple reasons why major software purchases fail, but one of the most common is that of an inadequate requirements analysis. The problem is caused by people being unfamiliar with requirements gathering techniques, and by grossly underestimating the amount of work involved. Requirements are to software selection as foundations are to a building. Get them wrong or leave things out and there always will be problems. This article examines the consequences of missing requirements in the analysis phase and describes how to avoid the problem in the first place.