Prepared by Gertrude Elles (1872-1960) and Ethel Wood (1871-1946), this monograph was originally issued in ten instalments between 1901 and 1914, with the title page and index appearing in 1918. It is reissued here in two volumes. A systematic description and illustration of over 370 species of graptolites known at that time from the British Isles, and including nearly 100 new species, it was prepared under the editorship of Charles Lapworth (1842-1920), who also wrote a short introduction and some general discussion on classification. Elles wrote much of the descriptive text and Wood prepared the hundreds of wash-drawings. The resultant monograph is valued for the accuracy of these illustrations; those on the plates were printed at natural size, enabling a user equipped with a hand lens to compare a rock specimen directly with the printed figures. The monograph was much admired and led to imitations, but none could match the quality of the original.