This book is for intensive care nurses. Intensive care nursing is a diverse speciality, and a text covering its every possible aspect would neither be affordable nor manageable to most clinical staff. This text, therefore, is necessarily selective, and will probably be most useful about 6 to 12 months into intensive care nursing careers. It assumes that readers are already qualified nurses, with experience of caring for ventilated patients, who wish to develop their knowledge and practice further. Discussion of clinical issues is therefore followed by implications for practice. Knowledge develops and changes; controversy can, and should, surround most issues. Some controversies are identified, others are not. But every aspect of knowledge and practice should be actively questioned and constantly reassessed. If this book encourages further debate among practising nurses it will have achieved its main purpose. Since a novice (Benner 1984) has little knowledge or experience, ‘basic’ nursing texts tend to explain almost everything. This book is for competent and advanced practitioners, however, whose knowledge and experience will vary. To help readers, ‘fundamental knowledge’ is listed at the start of many chapters, so that readers can pursue anything they are unsure about. Much ‘fundamental knowledge’ is related anatomy and physiology, and it would be a disservice to readers to displace other material for superficial summaries when there are many excellent anatomy and physiology texts available.