While some may be put off by the “For Dummies” series title, I have found most to be excellent starting points. Seasonal Affective Disorder for Dummies by Laura Smith and Charles Elliot is where I would suggest you begin if you have questions or interest in Seasonal Affective Disorder (SAD). It references up to date research in a practical, readable manner. It is very well organized and written.
While there is a very good chapter on Light Therapy, what I appreciate most is that most of the book addresses other interventions. What is known to date, is that effective treatments for depression are effective treatments for SAD. Another thing I like is how the authors give examples of negative thoughts in various chapters, followed by healthier thinking. Many will see their own negative thoughts and then see how they can begin to change it to healthier thinking.
If SAD is an issue for you, I highly recommend Seasonal Affective Disorder for Dummies.