This book presents the multifaceted aspects of rare earth elements (REEs), focusing on both their potential benefits and adverse health effects. The adverse impacts of REEs on human and environmental health raise a growing concern not only in the scientific community but also among a number of stakeholders, potentially including students, media workers, and decision makers. The recognized and potential benefits arising from REE-related technological applications may envisage their further advantages.

A limited number of books have been devoted so far to REEs, and they mainly focus on REE-related chemistry, mineralogy, economy, and developing technologies for these elements. This book presents recent research achievements in REE-associated health effects, which have been mostly confined to journal reports on individual laboratory studies so far. It is an updated and balanced approach to REE research and technology. It provides novel yet established information as stated in the title "At the Crossroads between Toxicity and Safety," with particular emphasis on the hormesis phenomenon.