I have known Bob Stahl since 1988 when I was Partner with him him and Chris Gray at RD Garwood Consulting. Bob has extensive experience working with S&OP and his books are a valuable asset for anybody wanting to learn more about IBP/S&OP.

Books available from:

Sales & Operations Planning: The How-To Handbook (3rd Edition)
Sales & Operations Planning The Executive's Guide
Sales Forecasting: A New Approach