As the most valuable commodity in the world and an enormous source of wealth, petroleum is the lifeblood of modern economies. It involves both governments and corporations — and, inevitably, politics. International oil economist and local author John Foster will explain the role of petroleum in today's conflict zones.  Registration is now full for this talk, which is free to adults, so any additional registrants will be added to a waiting list. If you have already registered but find yourself unable to attend, please cancel your registration at calendar.kfpl.ca/myevents or by phone at (613) 549-8888. Saturday, January 18, Central branch, at 2 p.m.