The aim of this masters thesis is to examine the synthesis and the structure of the main class for linguistics F in the Swedish classification system SAB. We want to find out whether F has developed towards a more faceted structure or not. Our theoretical perspective is based on fundamental principles for modern classification. To carry out our investigation the first, the fourth and the seventh edition of SAB is analysed and compared. The results of our study show that the main class F has become more faceted and therefore the possibilities to use synthesis have increased. Through synthesis more aspects of a subject can nowadays be expressed in F, and possibly in the entire Swedish classification system. The reason for this development may be the fact that SAB has been influenced by the faceted classification theory, first formulated by Ranganathan. Although F has become more faceted, we still consider it a mainly enumerative scheme since most of the subjects are enumerated and since there is only one place provided for them in the scheme. That F is a mainly enumerative scheme is maybe due to the fact that the system so far has been a fairly sufficient tool when it comes to organizing documents. Also, changing SAB into a faceted scheme would probably require much effort along with heavy expenses. However, in the future document collections will probably have grown in size and a more efficient tool for organizing them will perhaps be needed. Then it may be necessary to turn SAB into a faceted system.