CategoryBook: ''Crossing the Chasm : Marketing and Selling High-Tech Products to Mainstream Customers'' by GeoffreyMoore, 

http://images.amazon.com/images/P/0060517123.01._PE_PI_SCMZZZZZZZ_.jpg

ISBN:0066620023.

Pretty much essential reading for any commercial software designers. Should temper this book with GuyKawasaki's RulesForRevolutionaries.

''See also http://www.isa.org/~setex/pdffiles/982011.pdf''

A sequel to this book by the same author is InsideTheTornado.