Donations and sustainability always have been a subject of huge concern for non-profit leaders. Understanding the motivations of donor behaviour seems crucial to increasing pledges and loyalty and private donations have become one of the most widely researched topics in the funding of charities. This book explores what underlies donations practices, building upon an interdisciplinary approach, capturing key insights from the field of marketing and the prosocial behaviour literature. This books also provides an overview of the altruism and egoism debate, and a further comprehension of the religiosity effect on donations. It also includes expanded sections of motivations in the context of monetary donations and essential aspects of the non-profit sector. The research was carried out through thousands of extensive surveys and interviews mainly in Portugal but also in England. Readers will acknowledge how to develop a research into the motivations of donors, will learn how to integrate aspects of marketing and fundraising and profit from potential donors and best maintain a continuous donor base.