Porter Square Books, 25 White Street in Cambridge, welcomes Leslie Brunetta, a freelance writer whose articles have appeared in the New York Times, Technology Review, and the Princeton Alumni Weekly, as well as on NPR, on Tuesday, June 29, beginning at 7 pm.  Her wonderful new book, co-authored with Catherine L. Craig, Spider Silk: Evolution and 400 Million Years of Spinning, Waiting, Snagging, and Mating “cures arachnophobia for any lucky reader…”, according to Simon Levin, author of Fragile Dominion.  For more information, log on to www.portersquarebooks.com.