You're asking two questions here. First, about the quote. I'd say it's a mistake. The author hasn't been completely clear (and I think is possibly a little c

You're asking two questions here. First, about the quote. I'd say it's a mistake. The author hasn't been completely clear (and I think is possibly a little confused) over the difference between s-expressions in general, which are simply a tree-structured representation, and Lisp code, which is written as s-expressions but is subject to additional rules. In this case, it's pretty clear from the surrounding discussion that these s-expressions are not intended to be executable code. That being the case, there's no reason to use the quote. This line should have been > (keywords (list useless microframework academic swag)) Secondly, as others have mentioned, there is an important difference between symbols and strings that is not necessarily easy to explain -- indeed, it took the Lisp community a few decades to get clear on it. Fundamentally: strings are data; symbols are names. Notice, in this example, that all of the keys in the dict, as well as "dict" itself, are represented by symbols. That is because each of these names something in the domain of the program that manipulates the representation: an object type, an attribute of an object type, or, in the case you are asking about, a member of a set of keywords. If you've used enumeration types in a language that has them (C/C++, Java, C#, etc.), there's an analogy: symbols are like literals of a single, pre-existing enumeration type containing all possible names.