Nanomaterials have supported humankind’s advancement, becoming one of the most important industry sectors, and are expected to rise to the top by 2030. However, significant challenges must be overcome, such as the performance and efficiency of the material under different environmental conditions. This book seeks to promote a critical view on using nanomaterials under extreme conditions found in our body, planet, and outer space. Therefore, nanomaterials are covered from multiple points of view, allowing the reader to get an enriching presentation of current knowledge on nanomaterials, limitations, advancements, and applications under extreme conditions.