This article outlines an approach to marketing planning for radically new products, disruptive or discontinous innovations - those new products or services that change the dimensionality of the consumer decision process. The uncertainly that goes with radical innovation creates a great challenge for marketing menegers, but one that must often be confronted in high technology marketing. The planning process begins with an extensive situation analysis that pays particular attention to environment change coming from political,behavioral, economic, sociological, and technological source. These environmental forces are looked at from the points of view of the company, the business ecosystem or value network (what we used to call “the industry”), and the infrastructure. The stakeholders and factors identified in the situation analysis are woven into the economic webs surrounding the new product. The webs are mapped into Bayesian networks. This involves a combination of knowledge engineering and specificationof focused research projects. The Bayesian nature of the planning document enable planners to update information as events unfold and to simulate the impact that changes in assumptions underlying the web have on the prospects for the new product. This approach to marketing planning provides a dynamic alternative to a static planning document thaat is outdated before it is read. The method is illustrted using the historical case concerning the introduction of video tape recorders by Sony and JVC, and the contemporary case concerning the introduction of electric vehicles. A complete numerical concerning a software develoment project is given in an appendix.