“The illiterate of the 21st century,” Alvin Toffler famously said, “will not be those who cannot read and write, but those who cannot learn, unlearn, and relearn.” Our outlook on the world and our daily choices of disposition and behavior are in many ways learned patterns to which Toffler’s insight applies with all the greater urgency — the capacity to “learn, unlearn, and relearn” emotional behaviors and psychological patterns is, indeed, a form of existential literacy.

Last week, Oliver Burkeman’s provocatively titled new book, The Antidote: Happiness for People Who Can’t Stand Positive Thinking, prompted me to revisit an old favorite by Dr. Martin Seligman, father of the Positive Psychology movement, who was once elected President of the American Psychological Association by the largest vote in the organization’s history and under whom I studied in my college days. Learned Optimism: How to Change Your Mind and Your Life (public library), one of these 7 must-read books on optimism, was originally published 20 years ago and remains an indispensable tool for learning the cognitive skills that decades of research have shown to be essential to well-being — an unlearning those that hold us back from authentic happiness.

Seligman begins by identifying the three types of happiness of which our favorite psychology grab-bag term is composed:

‘Happiness’ is a scientifically unwieldy notion, but there are three different forms of it if you can pursue. For the ‘Pleasant Life,’ you aim to have as much positive emotion as possible and learn the skills to amplify positive emotion. For the ‘Engaged Life,’ you identify your highest strengths and talents and recraft your life to use them as much as you can in work, love, friendship, parenting, and leisure. For the ‘Meaningful Life,’ you use your highest strengths and talents to belong to and serve something you believe is larger than the self.

He then defines optimism and pessimism, pointing out the challenge to self-identify as either, and offers a heartening, heavily researched reassurance:

The optimists and the pessimists: I have been studying them for the past twenty-five years. The defining characteristic of pessimists is that they tend to believe bad events will last a long time, will undermine everything they do, and are their own fault. The optimists, who are confronted with the same hard knocks of this world, think about misfortune in the opposite way. They tend to believe defeat is just a temporary setback, that its causes are confined to this one case. The optimists believe defeat is not their fault: Circumstances, bad luck, or other people brought it about. Such people are unfazed by defeat. Confronted by a bad situation, they perceive it as a challenge and try harder. […] I have seen that, in tests of hundreds of thousands of people, a surprisingly large number will be found to be deep-dyed pessimists and another large portion will have serious, debilitating tendencies towards pessimism. I have learned that it is not always easy to know if you are a pessimist, and that far more people than realize it are living in this shadow. […] A pessimistic attitude may seem so deeply rooted as to be permanent. I have found, however, that pessimism is escapable. Pessimists can in fact learn to be optimists, and not through mindless devices like whistling a happy tune or mouthing platitudes…but by learning a new set of cognitive skills. Far from being the creations of boosters or of the popular media, these skills were discovered in the laboratories and clinics of leading psychologists and psychiatrists and then rigorously validated.

Seligman, however, also corroborates what’s perhaps Burkeman’s most central admonition — that the extreme individualism and ambition our society worships has created a culture in which the fear of failure dictates all. As Seligman puts it:

Depression is a disorder of the ‘I,’ failing in your own eyes relative to your goals. In a society in which individualism is becoming rampant, people more and more believe that they are the center of the world. Such a belief system makes individual failure almost inconsolable. […] Teaching children learned optimism before puberty, but late enough in childhood so that they are metacognitive (capable of thinking about thinking), is a fruitful strategy. When the immunized children use these skills to cope with the first rejections of puberty, they get better and better at using these skills. Our analysis shows that the change from pessimism to optimism is at least partly responsible for the prevention of depressive symptoms.

Ultimately, Seligman points to optimism not only as a means to individual well-being, but also as a powerful aid in finding your purpose and contributing to the world:

Optimism is invaluable for the meaningful life. With a firm belief in a positive future you can throw yourself into the service of that which is larger than you are.

Learned Optimism: How to Change Your Mind and Your Life was followed by Authentic Happiness and Flourish, which was among best psychology and philosophy books of 2011.