The health care of homeless persons: a manual of communicable diseases and common problems in shelters and on the streets James J. O'Connell, editor Boston, Mass: Guthrie Nixon Smith; 2004 345 pp US$15 ISBN 0-9711650-8-4 With tens of thousands of people in Canada estimated to be homeless on any given night,1 many Canadian health care workers frequently face the challenge of caring for homeless patients. But is health care for this population so distinct that we need a separate manual to guide us? An answer is given in the editor's introduction to this book: Caring for homeless persons requires a deliberate blurring of the traditional boundaries between institutions and among health care disciplines and professions. While physicians, nurse practitioners, and physician assistants can diagnose and treat according to Harrison's Principles of Internal Medicine, a homeless person with a lower extremity ulcer and cellulitis needs access to antibiotics and a place to keep the leg elevated, an impossibility while living in shelters or on the streets. Thus the clinician's treatment plan is only as effective as the social worker who obtains the medications, the nurses who perform the twice daily dressing changes, and the shelter supervisor who permits the person to remain in the lobby during the day. (abstract from the article)