Covers in 150 pages what "big name" books cover in 1000 pages.
The Kindle version is great, it even includes extensive color highlighting for easier reading.
If you have not written code in any language in your life then this book may be a bit dense.
If you have exposure to coding in a language with a C-like syntax, and even more if you have read a bit about Java here and there (you don't need to be able to write "hello world" from scratch) then reading this book before other books is the best investment of your time.
The book does cover the core parts (language, using the basic tools, using collections, doing I/O) but does not cover all libraries. The parts that are covered are covered reasonably comprehensively but it does not waste your time with anecdotes, contrived jokes or subjective rants that make most other books 5 times longer for the same amount of information.
I read it on mobile phone (with a 720x720 LCD) and it is great. All the code is real, readable text that can be highlighted, zoomed, etc., not like many other Kindle books where key information is included only in low-resolution images that is hard to read and cannot be manipulated as expected.