"In fact, human beings look at underground living with great disdain, whereas in the Greater Community it is recognized to be a tremendous advantage. Being surface dwellers your actions, gestures and forms of communication can be easily observed and deciphered. You are out in the open where eyes from beyond can watch you carefully. Your minds can be read. Though you may not be understood by those who observe you, your actions are nonetheless predictable and, therefore, many correct assumptions can be made about human behavior without a great deal of inquiry." 
"Your natural environment will become increasingly polluted, so much so that there will be whole areas of the world where people cannot live. People will take to living indoors more and more and will even explore the possibilities of living underground."
In the Greater Community
" Underground settlements have proven to be far more effective and accommodating, especially when you are actively engaged with other Greater Community powers. This gives you greater security and a greater opportunity to protect your physical resources and your population at large. However, living underground isolates you from biological elements in the outer environment, thus making you more susceptible to illness and attack by other kinds of organisms. This presents an interesting truth in the Greater Community: The more safe and secure you become, the more vulnerable you are." 
"Many advanced races live underground where they are able to sterilize their environment and thus protect their populations from disease very effectively." 
"You know not of the great disadvantage you are creating for yourself in broadcasting your communications into space. It is the problem of living on the surface of your world, where everything can be observed. Many advanced nations in the universe have chosen to live underground for this purpose, and some have chosen to live underground out of necessity, for if your planet’s climate system is disrupted, surface living becomes difficult if not impossible. Living underground has many advantages. Discretion is one of them." 
- Wisdom from the Greater Community II, Chapter 14: Intelligence
- Greater Community Spirituality, Chapter 18: What is human destiny?
- Greater Community Spirituality, Chapter 6: What is the Greater Community?
- The Allies of Humanity Book Three, Second Briefing: The Requirements for Freedom in the Universe