If you are an Oracle programmer, or a DBA that works with programmers (and has to tell them all the things that they are supposed to know) this is the best book you can buy.
There are books by people that can program, books by writers who can write but do not quite understand what they are writing about, and there are a million other faults a book could have. However, this book has none of them.
Tom Kyte is at the very top of Oracle programming and he is a teacher who wants you to be able the do the same thing. Every topic in this book "reaches the ground". Tom starts from setting up your environment, and takes you through many high level exercises, showing you how to make it work, every single step of the way.
There is too much to describe it all, but as an example, there is a 70-page section on writing a C-Based external procedure. It starts with six pages of setting up your environment (listener, schema, server, exproc program, libraries), then the code in PL/SQL and C, how to make it, how to install it, how to test it. It ends with the answer to every error message you might get if you make a mistake.
The applications discussed are not just "interesting" and they do not just "work". There is a recurring theme in all of the applications and that is this that they scale. Tom has sections on bind variable, and then more on bind variables, and then more on bind variables, until the idea is branded on you that a "working" application is trivial unless it scales. You are not writing code for developers, but for end users who may do millions of transactions a day; that is the kind of code you want.
If you already know everything, you will learn more! Either way Tom's projects are complete, and well documented.
This is great book, and you will read all 1200 pages.