Stylish, thoughtful but rather slow-moving alien-contact/coming-of-age yarn. The first colonists of planet Penterra were Quakers, and found no difficulty in accepting the native hrossa's ban on advanced technology and limitations on human breeding and expansion. But now a second shipload of colonists, non-Quakers, has arrived; these humans, called Sixers, intend to ignore the hrossa's strictures and build an Earth-type high-tech colony. The hrossa warn mildly but firmly that the planet itself will destroy the Sixers if they persist. Meanwhile, stimulated by the Sixers' arrival, the Quakers investigate their hosts' lifestyle, finding that all Penterran life is linked in an intricate and polite sexual-empathic chain. Young adolescent Quaker Danny, who alone of the humans has learned to speak hrossan, is caught between two worlds--the attractive family/sharing network of the Quakers and the dazzle of Sixer technology and knowledge. Then the hrossan warnings become actuality: the Sixer colony collapses as the humans, their live-stock, and food crops are unable to reproduce. Finally, Danny finds himself with the ability to eat and digest the native lifeforms. He has become integrated into the planet's life cycle--and thus points the way for human survival on Penterra. Charming work, with characters and setting portrayed in satisfying depth and with a well-articulated plot. But there are nagging, unanswered questions here: how did the alien sexual-empathic lifestyle come about? and how could intelligence evolve in the absence of competition? So: almost, but not quite, convincing.