Catalan's Constant to 1,500,000 Places is a mathematical work by Simon Plouffe, presenting the value of Catalan's constant (G) calculated to 1,500,000 decimal places. This book is a testament to computational mathematics, offering an extensive decimal expansion of this important mathematical constant, which appears in combinatorics and number theory. The work is part of Project Gutenberg's collection and serves as a resource for mathematicians, researchers, and enthusiasts interested in high-precision calculations and mathematical constants.