"However, this book is anything but" meaning

What's the structure and meaning of this sentence in the following text:

A friend lent this to me before I headed over to Italy and France this summer. I was a bit skeptical at first as he's heavily into the technical aspects of architecture. However, this book is anything but.

Solution 1:

"This [object] is anything but" is another way of saying "This is nothing like what I had initially thought about .. [that object]"

So the author thought the book given by his friend would not be to his liking, as the donor was "heavily into the technical aspects of architecture" and he was pleasantly surprised when that was not the case. The book was not as bad as he thought.

Solution 2:

...at first as he's heavily into the technical aspects of architecture. However, this book is anything but.

The sentence you italicized is saying the books is anything but "heavily into technical aspects of architecture.