Having worked in web and digital marketing for 15 years, I'm quite an expert myself. I bought this book for my daughter (it's a reference work for the Chartered Institute of Marketing course on Digital Marketing). Now she can learn everything I learned in 15 years, just by studying one book. So can you.
It's comprehensive, well written, well structured. Very pedagogical. It's not lightweight by any means, but the information is presented in a very digestible way. The structure of each section is "In this section you will learn XYZ. This is XYZ. Now you have learnt XYZ." - i.e. presentation, explanation, summary.
I highly recommend this book for anyone wanting to learn about digital marketing (check the contents list to see what it covers).