To quote from the Preface concerning what the difference between these two editions is:
"The Second Edition
Although Nand to Tetris was always structured around two themes, the
second edition makes this structure explicit: The book is now divided into
two distinct and standalone parts, Part I: Hardware and Part II: Software.
Each part consists of six chapters and six projects and begins with a newly
written introduction that sets the stage for the part’s chapters. Importantly,
the two parts are independent of each other. Thus, the new book structure
lends itself well to quarter-long as well as semester-long courses.
In addition to the two new introduction chapters, the second edition
features four new appendices. Following the requests of many learners,
these new appendices give focused presentations of various technical topics
that, in the first edition, were scattered across the chapters. Another new
appendix provides a formal proof that any Boolean function can be built
from Nand operators, adding a theoretical perspective to the applied
hardware construction projects. Many new sections, figures, and examples
were added.
All the chapters and project materials were rewritten with an emphasis on
separating abstraction from implementation—a major theme in Nand to
Tetris. We took special care to add examples and sections that address the
thousands of questions that were posted over the years in Nand to Tetris
Q&A forums."
I'd recommend watching the course material and reading each chapter. It depends on a little luck which material clicks and how quickly, for me it varied from chapter to chapter whether or not I could get by with just the videos.
Im currently taking this course without having the book and it works great. I might buy the book later but for me it’s important to have the imposed weekly deadlines in order to not just drift away and do something else instead.
I first tried the course many years back, and didn't complete it (not necessarily only because it was in course form). Last year I bought the 2nd edition book, and found it more accessible, as a do it on your own time type of project, and as a reference while implementing the parts.
The most recent edition of this book is the Second Edition: https://www.amazon.com/dp/0262539802/
To quote from the Preface concerning what the difference between these two editions is:
"The Second Edition
Although Nand to Tetris was always structured around two themes, the second edition makes this structure explicit: The book is now divided into two distinct and standalone parts, Part I: Hardware and Part II: Software. Each part consists of six chapters and six projects and begins with a newly written introduction that sets the stage for the part’s chapters. Importantly, the two parts are independent of each other. Thus, the new book structure lends itself well to quarter-long as well as semester-long courses.
In addition to the two new introduction chapters, the second edition features four new appendices. Following the requests of many learners, these new appendices give focused presentations of various technical topics that, in the first edition, were scattered across the chapters. Another new appendix provides a formal proof that any Boolean function can be built from Nand operators, adding a theoretical perspective to the applied hardware construction projects. Many new sections, figures, and examples were added.
All the chapters and project materials were rewritten with an emphasis on separating abstraction from implementation—a major theme in Nand to Tetris. We took special care to add examples and sections that address the thousands of questions that were posted over the years in Nand to Tetris Q&A forums."