It is attributed to Solomon probably because it is about love. Solomon is the patron saint of Old Testament wisdom, which is the search for the good life. Happiness in love is certainly part of the good life. This book is a collection of love songs which overlap into each other. There is no agreement as to where one song ends and another begins.
Refrains bind several together.
Sometimes the whole work is interpreted as a drama with first the woman speaking and then the man. The main speaker throughout, however, is the woman. This book has had a long history of interpretation. It is interpreted on the basic level, as a collection of songs about the wonder of human love. It has been interpreted as the love story between God and Israel.