This is a valuable book for learning QM, with an emphasis on Dirac’s &lt;BRA-KET&gt; notation. He spends much time on spin states, which is the simplest entry point to QM. He derives the Pauli Matrices, while developing linear operators. Admittedly it would be easier if one already knows vector spaces, complex vector spaces, inner products, eigenvectors, eigenvalues, Hermitian conjugates and operators, etc. But he does a fair job of introducing these things without the complexities that lie beneath. A good thing might be to more carefully distinguish between the real dot product and the more general inner product. And in turn why conjugation and transposing are necessary. A good grounding in linear algebra would be an advantage. He eventually moves on to the Schrodinger approach to QM, although I haven’t gotten that far. I think it would be difficult for anyone without some previous calculus, linear algebra, etc to absorb this book. On the other hand it’s excellent for those who have had a taste of those subject as a starting point for this book. It’s not an easy-read popular book, but not an oppressive text book either.<br>As I continue, So far, so good.