Bonus Chapter

It’s impossible to overstate how important reviews are for an author. Most book sales, at least for books without a marketing budget, come from people who find books through the recommendations on Amazon. Your review helps Amazon figure out what types of people would like my book and makes sure it’s shown in the recommended products.

I’d never ask anyone to rate my book higher than they think it deserves, but if you like my book, please take the time to write a short review and rate it on Amazon. This is the biggest thing you can do to support me as a writer.

Each review has an impact on how many people will read my book and, of course, I’m always happy to read about what people think about my writing.

So on that note, if you buy my book on Amazon and leave a review, I will send you a free bonus chapter. Simply send me a link or screenshot to your review on Amazon to or leave a comment here.



5 thoughts on “Bonus Chapter

  1. Dear Jakob Schwichtenberg,

    I mail you for two purposes; first, to see if I can get the bonus chapter. Second, too let you know what I think of it anyway.

    Sadly, I can’t leave a review on Amazon; Amazon has no payment options I can use, so I can’t leave reviews (requires more than one purchase).

    However, I have shared the book on my page [].

    Now, more importantly I’d like to tell you what I think of it. I’m a M.Sc. student in Delft, currently doing a research project of only 6 weeks. I have to do two of these for my rather strange M.Sc. program. The research project is at the Lorentz Instute in Leiden, and contrary to delft they do deal with theoretical physics, specifically quantum field theory, group theory and general relativity. Delft mostly focuses on nano-devices in the master program, so sadly these topics are missing.

    The Leiden group I’m working with/at/for gave me a text on group theory, but it seems to be written for mathematicians rather than physicists. I was rather bored with it, and couldn’t make much progress. I decided to hit the library for an e-book that was better fit for me. Group theory, as keywords, didn’t bring up much; but physics symmetry immediately yielded your book. Looking into it, I found a very modern website, an interesting preface and decided to download the book.

    I’m now at page 60, after a day. I’m enjoying the writing style – it is indeed very well suited to somebody that hasn’t got much introduction into it. I particularly like going from simple definition to abstract mathematical definition and back. The few errors that I did spot are already in your errata, so well done.

    What I would want to know, and what is missing from your author information, is where you are in your education. You mention working on a thesis, which would indicate a Master or Ph.D. student.

    Either way, well done on writing the book. My sincere thanks for that!
    – Josko Daimonie

  2. Jacob,

    Your book is not only an excellent book but an enlighten and deep source for understanding quantum field theory, otherwise difficult to grasp it. Very well done and wishing you the best in your career.

  3. Hi Jakob,

    Your book is amazing! Currently trying to self-study QFT and reps, and your book is invaluable. Your work is great, and physics needs more authors like you!

  4. Hi Jakob,
    Here is a reader from China. Your book is great and very inspiring, and I hope there could be more books like yours.

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