Religion within the Boundaries of Mere Reason (SparkNotes Philosophy Guide) Book

The Project of Pure Enquiry is an excellent introduction to philosophy, at least I am going to try and argue that it is. It is an excellent introduction because it does three challenging things very well. Firstly, it does what title suggests, and introduces the reader to the work of Descartes and his attempt at creating a foundation for human knowledge (Williams focuses on the Meditations and Replies, but also draws on other texts when doing so is helpful - such as The Passions of the Soul). Williams does this by carefully setting out for the reader his interpretation of Descartes' arguments, and how they fit together as one system. His aim in doing this is not really to show the reader what Descartes said, but to get the reader to engage with these problems on a philosophical level. Hopefully, the reader will finish the text having a vague idea of what they think Descartes got wrong, and what he got right.
Because Williams approaches Descartes in this way, his books is full of rigorous argumentation, and in some cases novel contributions to the field of philosophy. An example of the later is Williams' argument to the effect that we cannot choose what we believe. So, the second reason why this book functions as a good introduction to philosophy is that it just is excellent philosophy on the part of the writer (which is not the same as saying that he gets everything right).
The third reasons is closely related to one of its limitations. Though Bernard Williams is known for drawing on a lot of traditions, for the most part he remains within a particular philosophical tradition himself - that of English analytic philosophy. There are positives to this. The tradition is greatly indebted to Descartes, and as it clear from William's book that many of the problems being addressed in this field of philosophy find early expression in the work of Descartes (William's book is a testament to this overlap). Because of this, this book also offers a way into this type of philosophy that is sensitive to the historical underpinnings of much of the problems that are addressed, and demonstrates the analytic style that is often found in this tradition. Don't be put off by the publication date either (1978), much of these problems, and their descendants, are still being addressed today.
But this embeddedness within a particular tradition leads to two problems. Firstly, how on earth can this be an introduction to philosophy in general (as I have claimed) if it is already an instance of one type of philosophy. Secondly, can we really trust this work as an accurate exegesis of Descartes and his thought, if Descartes is being read through the eyes of 20th C Analytic Philosophy? I don't think we should worry about the first objection, if this limitation is recognized and accounted for. An introduction can never be fully representative, especially of a field like philosophy where one has to engage with actual philosophy to understand what it is all about. The solution here is to read other texts as well as this one, try to understand them as best as possible, and make up one's own mind about the value of the different approaches. Perhaps I should say that this book helps in introducing philosophy, without offering a full introduction (I'm not even sure what the later thing could be). To the second objection I don't really have an answer, since it is up to the reader to decide whether they think William's interpretation reflects the real Descartes or not. A book I would recommend as a companion to Descartes which doesn't bring with it any 20th Century baggage is Carriero's Between Two World - at least it does not do this explicitly. So, again, the remedy is to read more texts in addition to this one, not as substitutes. Perhaps it is best not to begin the project of pure enquiry at all, with all the reading it seems to require.