Just started this and after reading the introduction and going thru the structure of the book, I think I can safely make a statement to respond to all the persons who complain that this is not a good introduction to Buddhism, saying : .. it simply is not an introduction to Buddhism. It is a work that is targeted for people who have (already developed) an authentic interest in Buddhism and are in search of in depth source of objective knowledge about it's historically relevant texts.
For sure if you have no clue about Buddhism, and it is your wish to start with this work, you can, but it is going to be an extraordinary intellectual effort, so the question is just - how prepared are you for that task? I would say if you have no background in any related area (be it philosophy or other spiritual tradition or anthropology or what have you... ), it might be ambitious.
Now I am nothing if not supportive of ambition in intellectual goals, so have a go, but be conscious of what you are up to !
In my opinion, this book is especially valuable for people like myself who have read by now quite a few introductions to Buddhism, in distinct forms and flavors, from zen to theravada to mahayana to tibetan, I had a glimpse of all those, ... and now we are looking for some scholarly knowledge of the "authentic" texts, as they were compiled historically in different languages, traditions, etc. It will still be a glimpse of that too, the material is just too vast, as the anthologist Donald S. Lopez clearly informs.
This is most definitely not a "random" collection as some reviewers mentioned. Possibly they skipped the introduction where Donald S. Lopez explains his method and purpose. If some texts are boring... well, what can we do, the text is the text, we can't cheer it up a bit. This is an anthology, so in that light one should read or consult it.