Part 3 of Engler's Syllabus of Plant Families - "Bryophytes and seedless Vascular Plants" provides a thorough treatment of the world-wide morphological and molecular diversity of a part of "lower" plants [Marchantiophyta, Bryophyta, Anthocerotophyta, Polysporangiomorpha, Protracheophytes, Rhyniophytina, Lycophytina, "Trimerophytina", Moniliformopses (Cladoxylopsida, Psilotopsida, Equisetopsida, Marattiopsida, Polypodiopsida)], and Radiatopses (Progymnospermopsida). The advent of DNA sequencing and advances in phylogenetic analysis has raised new interest in the relationships of liverworts, mosses, hornworts, ferns, and fern allies as extant representatives of early land plant evolution. Following the tradition of Engler with the morphological-anatomical data and incorporating latest results from molecular phylogenetics and phylogenomics, an up-to-date overview of families and genera has been created that will serve as reference for a long time. Engler's Syllabus of Plant Families has since its first publication in 1887 aimed to provide both the researcher, and particularly the student with a concise survey of the plant kingdom as a whole, presenting all higher systematic units right down to families and genera of plants and fungi. In 1964, more than 40 years ago, the 12th edition of the well-known "Syllabus der Pflanzenfamilien" ("Syllabus of Plant Families"), set a standard. Now, the completely restructured and revised 13th edition of Engler's Syllabus published in 5 parts and in English language, for the fi rst time also considers molecular data, which have only recently become available in order to provide an up-to-date evolutionary and systematic overview of the plant groups treated. In our "molecular times" there is a growing need to preserve the knowledge of the entire range of diversity and biology of organisms for coming generations, as there is a decline in "classical" morphological and taxonomical expertise, especially for less popular (showy) groups of organisms. Accordingly, the 13th edition of Syllabus of Plant Families synthesizes both modern data and classical expertise, serving to educate future experts who will maintain our knowledge of the full range of Earth's biodiversity. Syllabus of Plant Families is a mandatory reference for students, experts and researchers from all fields of biological sciences, particularly botany.