Hello again, dear readers, and welcome to our monthly letters column. Even before the official start of summer, much of the U.S. was facing excessive heat, and it hasn’t let up as we’ve passed Independence Day. Whenever temperatures spike, please take care. Limit outdoor or strenuous activities, and stay hydrated. Use fans or air conditioners if you have them, take advantage of the air conditioning in a mall or visit a dedicated cooling center. One of our columns this week explores the symptoms and dangers of heat-related illnesses. If your own workplace is affected by extremes in the weather, this is a worthwhile read. And now, onward to your letters.