In this chapter, we discuss when, how, and why trust and trustworthiness arise to support cooperation within and across organizations. To do so, we first define trust and trustworthiness, discuss how they can be quantified and determine key components of trusting and trustworthy behavior. In addition, we identify building blocks of trust and trustworthiness and offer tangible insights about how to establish trusting and cooperative business/inter-organizational relationships, based on both academic research and case studies from across industries