This one is tough to grade. On the one hand, I learned a lot from the process of reading this book. On the other hand, I have severe issues with a lot of it's content. Let me explain.
I learned a lot from the process of reading this book, because it made evident and deepened further my understanding of the method of investing advocated by value investors, in perticular Buffett and Graham. Having their principles fresh in mind from recently read books, it was easy to spot some of the suggestions touted by Damodaran as unsound.
A shining example is that he seem to accept relative valation as a method deriving a valuation for a share, inspite of such a "valuation" beeing, in the end, totally dependent on market sentiment. I suppose if you accept the premise that markeds are fully efficient, this should blow past as acceptable as well. If you however belive, like me, that markets are not efficient one hundret per cent of the time, you will either: A) take issue with how relative valuation is prescribed in the book (in fairness to Damodaran, he does, in the last chapter of the book, admit that relativ valuation can answer only wheter the company is "cheap or expensive, given how the market are pricing other companies just like this one", but that is little to late after touting it as a metod of valuation through the book), or B) infer your purchase prices from a relative valuation and risk beeing one of the people standing when the music stops after a overheated marked/a bubble (imagine basing your investment decision in a tech. company circa 1999 on a realtive valuation).
I also take issue with presenting valuation of young growth companies based on significantly increasing the number of variables and necessary prerequisites and substitions by way if genereal inferrals as sound. In my view, a more sound approach would be to say that such a company does not realiably lend itself to valuation, as we have no way of predicting its cashflows within reasonable probabilities that the number derived from it is usable in any sense for any one (much less stake your hard-earned cash on the output you derive from it). Buffett says to stay within you should only value stocks within your circle of competence - stick to what you know, and know what you do not know. It would thus be sound to steer clear of valuing a company by way of a number of variables in need of prerequisites which are so high that the probability of the number deriving being correct when future becomes historie is fast-approching zero.
I also had my blood pressure somewhat elevated by how Damodaran seemingly condone adjusting the valuation (growth ratios or ROIC) based on the (!)chance(!) that a company may change management and that the new management augment the operations so as to acheive higher returns on invested capital (page 139) or that the company might sometime in the future venture into new markets or relase new, not-yet-thought-of products (par to adjusting Apples valuation based on the growth spurt made possible of the later relase of the iPhone cirka 1995) (page 100-101). Condoning to entertain such augmentations of the valuation despite it being no more probable than the company's headquarters being annihilated by an earthquake has a hard time standing up to the tests of logic.
In manners such as the above, it is my view that Damodaran througout the book either skeews towards illuminating possible positives without addressing equally probable negatives to the valuations. Lastly, but possibly more important, is that he through the book gives you an method for valuation of any company by way of adding variables, prerequisites and by-way-of-substitutions to get the requested output valuation. However, he does not help you destinguish between situations where a company lend itself to valuations where the output can be trusted even to be probable. That destinction you have to make for yourself.
If I were to rate the book on the learning experience reading it have given me, it would be five stars. On the content side, there definitly are positives. Part one - the valuation give a concise and comprehensible overview of the philosophy behing valuation and a brief overview of the necessary prerequisite knowledge. Damodaran's writing on the discounted cash flow model and it's working is also really good. So are his learnings on financial optimisation (page 132) for reducing weighted avrage cost of capital and his chapters on valuing financial service companies and cyclicals.
The good parts are really good and the bad parts could have been left out. The synthesis of my review: The little book of valuation is not small enough.
PS: I truly love Damodaran's online lectures and the way he selflessly shares his teachings and materials online. Any bias going into reading this book was in his favor.