This book contains 'selected writings' from Discourse on Method, Meditations on the First Philosophy and the Principles of Philosophy. To what extent they are 'selected' and therefore not the whole works I'm not certain, it rather iritatingly doesn't explain anywhere in the book itself. I will check by comparing them to another edition at some point, but it loses a star anyway for not being clear.
Other than that I entirely recommend the book, it's quite small (about A6 size) but hardback as well which is nice. Despite being small it also contains a nice concise introduction to Descartes life and works. I hardly feel I need to review the actual work of Descartes (indeed I hardly feel qualified to review Descartes work). But it's probably worth explaining that 'Discourse' is his attempt to reach fundamental philosophical truths and leads to the statement 'cogito ergo sum', 'I think therefore I am'. 'Meditations' expands this and also gives an ontological argument for the existence of god. 'Principles' as the name suggests is a succession of principles which Descartes believes should be applied by the philosopher.
Perhaps most importantly for me, the language used is easy to understand, I can't stand it when translators make books intentionally and unnecessarily obtuse. Definitely suitable for someone who wants an introduction to some of this great philosopher's thinking.