 The book gives an analytical treatment of themes and motifs, particularly the ubiquitous serpent and dragon motifs, and a review of the 'material arts', such as the composition of temple facades, roof combs and mask panels.Spinden's chronological treatment of Maya art was later (1950) refined by the motif analysis of the architect and specialist in archaeological drawing, Tatiana Proskouriakoff, in her book 'A Study of Classic Maya Sculpture'.Kubler's 1969 inventory of Maya iconography, containing a site-by-site treatment of 'commemorative' images and a topical treatment of ritual and mythical images (such as the 'triadic sign'), concludes a period of gradual increase of knowledge that was soon to be overshadowed by new developments.