The thesis provides an in-depth investigation of the significance of specific ethical experiences for humanitarian aid work. Following Emmanuel Levinas's and Martin Buber's understanding of ethics as arising from intersubjective encounters, I analyse four contemporary humanitarian aid workers' memoirs, and investigated the experiences humanitarian aid workers describe as being crucial for their humanitarian engagement revealing the nature of the specific encounters in which they arise as an ethical subject. In doing so, I explored three aspects: first, the role of particular experiences for humanitarian aid workers' motivation to work in the humanitarian sector; second, the role of particular experiences for humanitarian aid workers' ability to cope with the challenging nature of their work; and third the commonalities among these experiences.