Despite the introduction of innovative technologies and accurate laboratory techniques, an adequate anamnesis still remains the most important tool to develop a correct diagnosis. When signs and symptoms described by the patients are unusual, the correct identification of the disease becomes a very hard challenge for the clinicians. This book aims at providing a support in the interpretation of the most unusual signs and symptoms that can be encountered in the clinical practice. Each sign is described in concise way (one sign/one page): a full description of the symptoms as experienced by the patient is given, followed by its clinical meaning, the diagnosis and therapeutic approach. The book collects 30 unusual symptoms that could be encountered by the clinicians.