The important message of this book is that optimistic thinking is a very important skill that can be learned. But what is meant by optimistic thinking in this book? Well, to make sense of what happens in their life, people tend to attach explanations to events after they have happened. This process is usually referred to as 'attribution'. Seligman describes how people differ in their explanatory style, in other words, they have different 'habits of explanation'. He distinguishes three dimensions of attribution: 1) permanence (is the cause of the event permanent or temporary?), 2) pervasiveness (is the cause of the event general or specific?), and 3) personalization (is the cause of the even internal -personal- or external - caused by the sitution?). The difference between optimists and pessimist can be described using these three dimensions.
Pessimists tend to believe that negative things that happen to them 1) will have a long-lasting effect, 2) will affect many situations, and 3) are caused by themselves. Also, when something positive happens the pessimist tends to explains this negatively by 1) thinking this is just temporary success, 2) won't help him in other situations than this specific one, 3) and is caused by the situation more than by his own competence.
Optimists explain situations exactly the other way around. They tend to think that negative events 1) are just a temporary setback, 2) only affect thìs situation, and 3) are externally caused (not their own fault). Positive things are also explained positively by the optimistic thinker. He will think 1) that the success will last long, 2) that the success will positively affect other situations as well, and 3) that the success was caused by his own doing.
What's the relevance of this? Pessimists, by their way of thinking, constantly tend to destroy their own hope and build self-blame en guilt. A pessimistic thinking style causes many problems: emotional problems, under-utilization of your potential, and health-problems. Thinking pessimistically is a dangerous habit. It is a self-fulfilling prophecy: by thinking you have no way of influencing a bad situation, this becomes true. Optimists, on the other hand, build hope and maintain a positive self-image. They perform better at school and/or work, and are, on average, healthier. If this sounds interesting to you, maybe you should read this book. It will help you to assess your own habits of explanation and helps you to develop the skill of thinking positively.