The pinewood nematode (PWN), Bursaphelenchus xylophilus, is a plant parasitic nematode that has become, in the last century, one of the most damaging threats to pine forests around the world. This pathogen reproduces remarkably fast, is noticeably adaptable to new environments and capable of finding new transmission vectors and new hosts. Outside its natural range of North America, the PWN has created havoc in Asian and European pine forests with massive economic and ecological damages to affected countries. Despite the large economic investment in material and human resources to implement preventive and control measures, the PWN has maintained an alarming spread rate on a global scale. Presently, in the EU, it appears to be contained in Portugal and a handful of foci in neighbouring Spanish pine forests, however, due to its ease of spread and the oncoming environmental conditions imposed by climate change, the PWN is predicted to affect pine forests of contiguous EU countries of central Europe in the next decades. This chapter offers an updated discussion on the various aspects of PWN history, taxonomy, infection cycle, transmission, impacts, diagnostic and control measures.