I read that, too. But I'm not sure what he means by 'Only lists are by default'. If he means that only lists have a literal representation, then it would be sli

I read that, too. But I'm not sure what he means by 'Only lists are by default'. If he means that only lists have a literal representation, then it would be slightly wrong - since Common Lisp has literal representations for various numbers, symbols, characters, strings, vectors, arrays, structures, pathnames, ... Plus the s-expression syntax is user-extensible - making it as 'homoiconic' as the user needs it.