This book is what it says it is. That is, merely an introduction, but it is easy to read and rather than skim through complex concepts, Tudor Jones sets out the key facets to each idea and the main thought associated with each philosopher. I know many of us have picked up books like Machiavelli's Prince, or Rousseau's Social Contract only to get lost 10 pages later. So I would reccomend that you read this first, it would give you a greater appreciation and understanding of the original philosphy texts should you wish to pick them up.
Jones covers roughly ten thinkers inculding, Machiavelli, Rousseau, Hobbes, Locke, J.S Mill, Burke and of course Marx. And boxes explaining the background and lives of these thinkers are included within each chapter. I think it's a good read for both those who are wishing to delve into modern political thinking and those who have already read works like Emile, Das Capital, and the Prince who wish to gain a better understanding. And if you are using this book for an essay or project, there is a great list of references and recommended reading on each thinker and subject included at the back of the book.