Conceptual Geometry of Straight Line: A Companion to S. L. Loney's Co-ordinate Geometry. This work contains conceptual solutions to the problems and exercises given in Chapters I-VI (Covering Straight Line) of S. L. Loney's Co-ordinate Geometry including variations of problems, solutions, methods and approaches. These solutions strengthen and enliven the inherent multi-concepts to enrich the heritage set forth by S. L. Loney. The present work will serve as a complete guide to private students reading the subject with few or no opportunities of instruction. This will save the time and lighten the work of Teachers as well. This book helps in acquiring a better understanding of the basic principles of Straight Line (Co-ordinate Geometry) and in revising a large amount of the subject matter quickly. Care has been taken, as in the forthcoming ones, to present the solutions with multi-concepts and beyond in a simple natural manner, in order to meet the difficulties which are most likely to arise, and to render the work intelligible and instructive.