This is an essential book for diagnosis in psychiatry.
Morisson here teaches us how to make a differential diagnosis and what to do when information sources conflict which is very important because we face it a lot in practice.
He clarifies how to resolve uncertainty in diagnosis and one of the most important things I've learned from this book is not to jump to conclusion and diagnosis without enough information and the importance of the term "undiagnosed" when we don't we have enough information.
And although he stresses the rule that don't go for multiple diagnosis when one diagnosis can explain the patient's symptoms, he clarifies when to look for multiple diagnosis.
I recommend this book for anyone starting psychiatry or anyone who is working as a psychiatrist and didn't read it before.