This monograph has added a new material to the science of the history of architecture on Lithuanian wooden churches, chapels and belfries. Plentiful data of historical and natural investigation are analysed and systematised in the book. In the research study: a) the types and variants of the solutions of sacred buildings are fixed, b) the development of the types of architecture through each historical period to the year of 1918 is revealed, c) the interrelation between folk and professional architecture in the composition of buildings is explained, d) distinctive features of church architecture in Lithuanian ethnic regions and the relationship with the buildings from neighbouring sites is investigated.

The results allow to make these generalised conclusions:

1. Lithuanian wooden sacred buildings are an intermediate link between the folk and professional architecture. The two trends are combined in their composition with the folk or professional element dominant alternatively.

2. The folk trend is characteristic of the stability, functionality and the simplicity of the solutions of architecture. The most important folk compositional means are: the concord between the silhouette and the proportions, moderate shapes, featuring of the semantic accents, the subtile co-ordination of colour and texture.

3. The influence of the professional element upon wooden sacred buildings was twofold: indirect-featuring individual forms of the style and direct ­ with repeated compositional principles of the styles of architecture.

4. The composition of Lithuanian wooden churches, chapels and belfries is closely related to the arrangement of sacred buildings on Western sites of the Grand Duchy of Lithuania and North-Eastern areas of the Kingdom of Poland. This territory forms the area of an indivisible architecture. In the comparison of wooden sacred buildings of this area to the ones of other European regions, such as Norway, Northern Russia and Carpatho-Ukraine fundamental distinctions can be found.The composition of folk churches, chapels and belfries of the area is more laconic than that of complex and abundantly decorative sacred buildings on the sites mentioned.

Numerous wooden sacred buildings over the area built according to the style principles of professional architecture have not spread throughout other European regions.