Some of us never had a good caretaker, so I feel the way the author framed this can feel a bit condemning for those who didn't. I've had to learn 'successful solitude' in my life simply by finding peace and depth while alone because there was no alternative. It also feels a bit harsh to say that people are very lonely "simply because they can't form relationships." I was married for 17 years, but then I divorced and have been single for over 6 years since then, and in mid-life I do experience loneliness because I have not re-partnered, and my daughter has gone to college, and I find it very hard to find close companionship/intimacy when most people already have their 'primary' loved ones as priorities in their lives. Also, I'm not interested in superficial relationship, and prefer my own company to that, but it's harder the older one gets to find people with whom one genuinely feels sympatico. So, while I have many acquaintances and friends throug activities I've done with them for years, they haven't become "relationship" material as most of their time is spent with their own families and primary loved ones. You might say I am one of those people who is lonely, but I don't know if it's necessarily because "I can't form relationships." Nevertheless, I agree with your premise that solitude can be a great gift. I just don't agree that one should be labeled as someone who 'can't form relationships' if one never had a good relationship with a caregiver as a child, or if one is a mid-life adult who has gone through divorce and the deaths of multiple loved ones (I've had 6 in the past 7 years).