The solar debate continues this week as Grist readers pooh-pooh PV and extol the virtues of passive-solar design, a set of techniques that enable a house to be more efficiently heated and cooled just by sitting there. Several newly slim readers protest our gloomy predictions of environmental ruin brought about by popular high-protein, low-carb diets like Atkins; they testify that low-carb is possible with vegetables, soy, and free-range, enviro-friendly beef. Sadly, we've received no word yet on passive dieting. Finally, this week's batch of mail brings a heartwarming story of family reunification. For all this and much more, read our Letters to the Editor -- only on the Grist Magazine website.