In this issue of Infectious Disease Clinics of North America, guest editors Drs. Naomi P. O'Grady and Sameer Kadri bring their considerable expertise to the topic of Complex Infectious Diseases Issues in the Intensive Care Unit. Affected immunity of patients with COVID-19 has made management of complex infectious diseases in the intensive care unit more important than ever. This issue provides key updates for managing these complex infectious diseases and includes current clinical information for COVID-19 patients, making this a state-of-the-art collection of review articles for practicing infectious disease physicians. Contains 13 practice-oriented topics including timing and spectrum of antibiotic treatment for suspected sepsis and septic shock; preparing an ICU for a lethal viral respiratory pandemic; rapid implementation of a system-level ICU pandemic surge staffing amidst quarantined staff and infection control barriers; management of serious SARS-CoV-2 infection with immunotherapies; supportive care in patients with critical COVID-19; and more.  Provides in-depth clinical reviews on complex infectious diseases issues in the ICU, offering actionable insights for clinical practice.  Presents the latest information on this timely, focused topic under the leadership of experienced editors in the field. Authors synthesize and distill the latest research and practice guidelines to create clinically significant, topic-based reviews.