The events of 9/11 and the continued fear of terrorism have caused the federal government, many cities, and private building owners to rethink issues of public accessibility, open space design and perimeter building protection.  Our public realm is changing in major and minor ways through both incremental steps and revolutionary actions.  Who is making design decisions about our public space and security?  What are the motivations for these changes?  What does the new, secure public realm of Boston look like?  Susan Silberberg explored the actors, actions, and larger historical context of the current secure design trend in a lecture at the Boston Public Library sponsored by the Boston Society of Architects.