In the Little Mathematics Library now we come to Systems of Linear Inequalities by A. S. Solodovnikov.

This booklet is one of longest in the LML series, having more than 120 pages. The back cover of the book says the following about the book.

The book tells about the relation of systems of linear inequalies to convex polyhedra, gives a description of the set of all solutions of a system of linear inequalities, analyses the questions of compatibility and incompatibility; finally, it gives an insight into linear programming as one of the topics in the theory of systems of linear inequalities. The last section but one gives a proof of the duality theorem of linear programming. The book is intended for senior pupils and all amateur mathematicians.

And the preface adds

Until recently one might think that linear inequalities would forever
remain an object of purely mathematical work. The situation
has changed radically since the mid 40s of this century when there
arose a new area of applied mathematics -linear programmingwith
important applications in the economy and engineering. Linear
programming is in the end nothing but a part (though a very important one) of the theory of systems of linear inequalities.
It is exactly the aim of this small book to acquaint the reader
with the various aspects of the theory of systems of linear inequalities, viz. with the geometrical aspect of the matter and some of the methods for solving systems connected with that aspect, with certain purely algebraic properties of the systems, and with questions of linear programming. Reading the book will not require any knowledge beyond the school course in mathematics.

The book was translated from the Russian by Vladamir Shokurov and was first published by Mir in 1979.

You can get the book here.

There is a Spanish version of this as well (credits to IA user danni229)

The Link to Spanish version

The following is the table of contents

CONTENTS
Preface 7
1. Some Facts from Analytic Geometry 8
2. Visualization of Systems of Linear Inequalities In Two or Three Unknowns 17
3. The Convex Hull of a System of Points 22
4. A Convex Polyhedral Cone 25
5. The Feasible Region of a System of Linear Inequalities in Two Unknowns 31
6. The Feasible Region of a System in Three Unknowns 44
7. Systems of Linear Inequalities in Any Number of Unknowns 52
8. The Solution of a System of Linear Inequalities ‘by Successive Reduction of the Number of Unknowns 57
9. Incompatible Systems 64
10. A Homogeneous System of Linear Inequalities. The Fundamental Set of Solutions 69
11. The Solution of a Nonhomogeneous System of Inequalities 81
12. A Linear Programming Problem 84
13. The Simplex Method 91
14. The Duality Theorem in Linear Programming 101
1.5. Transportation Problem 107