Prof. Lehmann has continued his research on liquid crystals for seven years since his 1904 book, producing many papers and leading to a new book. The subject is complex and requires special equipment, and has received little attention in this country. Lehmann has given demonstrations in Vienna and Paris, and the author hopes for one in London. His conclusions are widely accepted, as seen in the remarks of Prof. Wallerant. The field of crystallography has evolved to show interdependence between its branches, and Lehmann's work shows crystals play a role in life processes. His research, which began nearly forty years ago, was initially met with skepticism but is now widely accepted. The book provides a coherent overview of his work, including descriptions of the crystallisation-microscope. Lehmann argues that crystals are not necessarily rigid, but can be solid or liquid, and that their anisotropic nature is fundamental. He suggests that crystals are involved in the growth of living organisms, as shown by the silicate-vegetation. The book is well-illustrated and well-written, with good printing and paper. The author also discusses the tidal survey of Japan, where Prof. Hirayama presents results from tidal observations. The work was carried out with Japanese thoroughness, and the author notes the use of a tidal abacus for data processing. The work involved extensive data reduction over sixty-six years.Prof. Lehmann has continued his research on liquid crystals for seven years since his 1904 book, producing many papers and leading to a new book. The subject is complex and requires special equipment, and has received little attention in this country. Lehmann has given demonstrations in Vienna and Paris, and the author hopes for one in London. His conclusions are widely accepted, as seen in the remarks of Prof. Wallerant. The field of crystallography has evolved to show interdependence between its branches, and Lehmann's work shows crystals play a role in life processes. His research, which began nearly forty years ago, was initially met with skepticism but is now widely accepted. The book provides a coherent overview of his work, including descriptions of the crystallisation-microscope. Lehmann argues that crystals are not necessarily rigid, but can be solid or liquid, and that their anisotropic nature is fundamental. He suggests that crystals are involved in the growth of living organisms, as shown by the silicate-vegetation. The book is well-illustrated and well-written, with good printing and paper. The author also discusses the tidal survey of Japan, where Prof. Hirayama presents results from tidal observations. The work was carried out with Japanese thoroughness, and the author notes the use of a tidal abacus for data processing. The work involved extensive data reduction over sixty-six years.