This book for serious students of and advanced practitioners in the field of surveying provides a comprehensive guide to the use of the 50-centimeter slide rule in the disciplines of tacheometry and curve ranging. Unlike many similar texts which are limited in their scope to smaller-sized models of the tool, the author demonstrates here how the 50-centimeter slide rule's greater accuracy and capacity enables it to meet a wider range of functions and applications. The author begins by explaining the advantages of this tool in resolving the mathematical calculations required to determine both horizontal distances and differences of level in tacheometry as well as the various coordinates (Latitude, Departure), thereby providing an accurate method of plotting survey information on a map. The second section of the book is devoted to curve ranging, in which the author describes suitable techniques for setting out curves for light railways, tramways, and other similar lines or pathways, even when the intersection point is inaccessible. The author's methods discussed within provide a level of accuracy that rivals those achieved using theodolite without the need for extensive tables. Throughout, the author provides clear formulas, worked examples, and a concise table of cosine squares and cosines for the reader's reference. The methods and examples given here help to demonstrate how slide-rule proficiency can improve efficiency and accuracy in surveying, particularly in the disciplines of tacheometry and curve ranging.