This is the ‘First Edition’ of Leonhard’s popular lectures on geology. The work is regarded as one of the finest popular works of the 19th century in this field. It covers topics such as mining, the history of the Earth, mineralogy and volcanology. Karl Cäsar Ritter von Leonhard (1779–1862) was a prominent German mineralogist and professor at the University of Heidelberg. The work covers, in 87 lectures, topics including mining, mineralogy, the formation and stratification of rock types, palaeontology, gemstones and metals, meteorology, volcanism, the Earth’s water cycle, etc. The work consists of five volumes in total, published between 1836 and 1844. Together, they contain 96 (of 97) steel engravings and lithographs, some of which are hand-coloured. Volume One: X pp., pp. 12–456, plates I–XIV Volume Two: 481 pp., plates XV–XXXIX Volume Three: 628 pp., plates XL–LXVIII; plate ‘XLVI’ bound upside down and therefore trimmed Volume Four: 490 pp., plates LXIX–LXXX; pages more heavily browned Volume Five: 712 pp., plates LXXXI–LXXXXVII; plate ‘LXXXI’ missing Stuttgart: Schweizerbart 1836–1844 Modern half-leather bindings with leather corners, 5 volumes, complete, marbled edges all round Over 2,700 pages and 96 (of 97) plates; plate ‘LXXXI’ is missing Size 19 x 13 cm each Condition Covers slightly rubbed and bumped; 1 plate trimmed; 1 plate missing; pages partly slightly foxed and browned, with more pronounced browning in volume 4