Imaginary Quantities: Their Geometrical Interpretation is a book written by Jean Robert Argand and originally published in 1881. The book is a mathematical treatise on the topic of imaginary numbers and their geometrical interpretation. In the book, Argand presents his eponymous Argand diagram, a graphical representation of complex numbers that is widely used in mathematics today. Argand's work was groundbreaking in its time, as it helped to establish the legitimacy of imaginary numbers and their role in mathematical analysis. The book is divided into several chapters, each of which explores a different aspect of imaginary numbers and their geometric interpretation. Overall, Imaginary Quantities: Their Geometrical Interpretation is a seminal work in the history of mathematics, and an essential read for anyone interested in the development of complex analysis and the theory of numbers.This scarce antiquarian book is a facsimile reprint of the old original and may contain some imperfections such as library marks and notations. Because we believe this work is culturally important, we have made it available as part of our commitment for protecting, preserving, and promoting the world's literature in affordable, high quality, modern editions, that are true to their original work.