Services were held Tuesday in Arcadia for Robert John Pierson, who died of AIDS-related illness on March 21, at the age of 41. Pierson, who grew up in Arcadia, authored "The Beach towns: A walker's guide to LA's Beach Towns" and was co-author of "LAbyrinth: A student's guide to Los Angeles." At the time of his death he was living in West Hollywood and teaching at USC.