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.



7 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.

  5. Hi Jakob

    Indeed a great textbook, filling a gap for those having to teach “introductory QFT ” and even after having to review some sessions.

    There are so many manuals treating the subject(s) about symmetry with a level leading rather to confusion rather than a tool helping to climb up by clear explanations!

    And you made it Great! You achieve this task with Brio and many thanks.

    Just consider ( note to all readers ) all the numerous paragraphs where you notice the author, taking you by the hand for a clear understanding about such many topics!

    A random example: p 88, naming, specific notes, recalling, bold essential definitions-objectives……

    randomly again….pp 137-138 no way to miss any step!

    This is a great Great Job achieved!

    More than recommended, I strongly invite to write a “wish” to any Uni. Lib. for having such written lectures within the shelves.

    Best regards


  6. Dear Jakob,

    I’m a middle age man, and I got my Physics degree many years ago. Unfortunatelly I wasn’t able to dig more in a Physics trough a Ph.D and I took another professional path. However, my interest in physics never decreased. Therefore I wanted to start reading about QFT at my own paceful speed and how the symmetry can help understanding it.

    This book astonished me from the first page. Is very clear and has many clarifying notes on the margin. Your sentence: “I wish I had existed this book when I was a student” is a perfect definition of the book. It sheeds ligth into the topics which looked strange at those days: quaternions, Lie double covereage, now they become natural even after many years of not being engaged in physics.

    Honetly it’s the scientific FIRST book which makes me want to reach home as soon as possible to continue the reading. The more I read the more beatiful I found the nature. It raised me two questions:

    Why the universe follows such a beautiful rules?
    Why this book wasn’t written in my old student days? (There are topic which are ESSENTIAL to tackle QM and SR for the begginers)

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