For the purposes of this book, I will use a simpler definition based on the pioneering work of Derek Abell (1980), who held that a business model is the sum of the answers that a company gives to these three interrelated questions:

Who should I target as customers?
What products or services should I be offering them and what should be my (differentiated) value proposition?
How should I do this in an efficient way?
While I do not pretend that the definition adopted here is exhaustive or better than all the others proposed by other people, I do believe that it is adequate for the purposes of exploring business-model innovation.