The longest familial relationship in life is with our siblings. It shapes our upbringing and our personality. Nevertheless, sibling relationships play a marginal role in counseling, education, youth services, and therapy, and when they do become a topic, the conflicting aspects of sibling relationships are often emphasized. This book aims to highlight the positive aspects of siblinghood and to make the findings of sibling research usable for training and education. The compilation of relevant theoretical aspects and practical examples provides professionals in counseling, education, and therapy with support to integrate the latest research findings into their professional work. Contributions from Dorothee Adam-Lauterbach, Alexandra Bernholt, Inés Brock, Lu Decurtins, Helmuth Figdor, and Jürg Fric.