William Young, senior preservation planner for the City of Boston Environmental Department, will lead a tour of Back Bay alleys beginning at The Gibson House Museum, 137 Beacon Street, on Tuesday, June 16, beginning at 5:30 pm.  The event is free for Gibson House Museum members and $10 for non-members.  Space is limited.  RSVP to 617-267-6338, or email info@thegibsonhouse.org.