The title of this post will invariably offend some readers as they will associate Mars with men and Venus with women. Maybe instead I should have said direct materials are from Jupiter and indirect materials are from Saturn. But the point of this post is not to associate a gender-bias with either category. Instead, the point of the planet metaphor is that direct and indirect materials are two very different worlds. Both involve the procure-to-pay cycles for products, but for very different kinds of products.