Virtual endoscopy progressively enters the real world The development of virtual reality is one of the most striking features of our Western societies. Beside chil­ dren games and movies, its scope has expanded to medical imaging through 3D CT scan surface or volume re­ constructions. Whatever the site clinicians are able to perform real endoscopy (RE), radiologists can now also provide virtual endoscopy (VE) images. VE enters our medical practice. The next question is to weigh the pros and cons. VE has the unique advantage to offer high-quality images obtained through a noninvasive and well-tolera­ ted procedure performed in outpatients. Compared to RE, it carries no risk of bleeding, perforation or trans­ mission of viruses. Importantly, VE can pass high-grade stenoses affecting large bowel, urinary tract or tra­ cheobronchial tree, and visualize areas hard to visit by optic fibers such as intracranial regions. 3D VE images can be commented with patients, and this might reduce potential misunderstanding and its medico-legal consequences. Last but not least, VE is the sole alternative offered both to those who refuse RE, and to severely ill elderly patients. Then, should we consider VE as the Deus ex machina of modem medical imaging - with CT scan as rna­ china - ? Clearly, the answer is no, given VE knows severals limits and pitfalls. One of the most important me­ rits of this book is to discuss honestly these aspects. First, VE will never allow to perform biopsies or resections.