[5-5] Given the name of a class, how can I get the names of its slots?

(defun class-slot-names (class-name)
  "Given a CLASS-NAME, returns a list of the slots in the class."
  (mapcar #'clos:slot-definition-name
          (clos:class-slots (find-class class-name))))

(defmethod class-slot-names ((instance standard-object))
  "Given an INSTANCE, returns a list of the slots in the instance's class."
  (mapcar #'clos:slot-definition-name
          (clos:class-slots (class-of instance))))

You can use CLASS-DIRECT-SLOTS instead of CLASS-SLOTS if you don't
want inherited slots. Note that these functions are from the
meta-object protocol specified in the original X3J13 draft spec
(document X3J13/88-003), and may not be supported by all Lisps.