Fernando Cacciola's Optional library is accepted into Boost. The review process was complicated by continual revision of the Optional library, and for this reason at least one reviewer favored rejection of the library at this time. However, the author and reviewers were quick to respond to interface revisions and were able to settle on a final interface, so the complications arising from interface fluctuations did not appear serious enough to override the majority of reviewers favoring acceptance. Doug Gregor Review Manager, Optional library