Actually, I'd give it 3.5 stars. Excellent exposition and developement of material. However, there are quite a few typo's that would throw the reader with less math off the trail (and possibly some with good math). Good coverage of different types of cases, underlying math, real world appications and properties of solutions. Personally, I would have preferred all the rigorous material (including math proofs) in the one book rather than making statements and referring to seminal real options papers very often. Some credit is due here, however, as there are some proofs in appendices at the end of each chapter - I think these could have gone into a little more detail and depth - (I say this only because there isn't the vast library of books on this subject that exists for more mature disciplines - guess I was looking for a more comprehensive reference.) I have read Trigeorgis' other books so this was not an introduction. Liked the book, learnt a lot and am applying it to real life projects, however had to learn a fair bit on my own too.