This book, from the International Psycho-oncology Society, is the second in a series of Companion Guides for Clinicians. The series editors identified a need for a guide to focus on the impact of cancer and oncology treatments on sexual health, fertility, and relationships. This brief manual takes a psycho-oncology perspective, placing the emotional, behavioral, and social elements at the center of the topics covered in the chapters. The aim is to describe approaches and treatments that cancer clinicians, mental health professionals, psycho-oncologists in training, and allied psychosocial oncology professionals can use. It emphasizes the importance of multidisciplinary care. The guide is not intended to replace national clinical guidelines and policies but gives a more generic international overview of factors that need to be considered when dealing with these issues in cancer patients along the treatment trajectory. Topics include management of sexual health, onco-fertility care, and relationship issues. The manual covers standards of good practice across all cancer patients, as well as focusing on the needs of individuals, couples, young people, and LGBT+ groups in a pragmatic format for use in everyday practice. Assessment methods are covered, alongside psychological treatments, encompassing a range of patient ages and cancer types. Policies and service, legal, ethical, confidentiality, and communication issues are covered. This manual can be used for quick reference. This will suit oncology professionals who decide to look further into a topic on a case-by-case or problem-focused basis as they undertake clinical work.