I bought this book a week ago and my confidence in diagnosis has increased ten fold. Not only can you pick the symptom you think is most relavent and look up what could be causing it, you also get a list of conditions with associated features, and how the condition is confirmed.
In real terms when on for example A&E, you get a patient with difuse hair loss (I had no idea where to start on this one) and you get given options of cytotoxic drugs , iron deficiency, sever illness, hypogonadism and recent pregnancy. You would then see what the symptoms of each are, and how you would confirm each.
It made the situation of coming away from a patient totally confused much easier. I am also better at coming up with differentials now.