I'd like to be certain about the focal length written on the cropped lenses, e.g. I have a Sony NEX-5N with the original OSS 18-55mm kit lens. Is it actually an 18 to 55mm focal length with no "recalculation" from the manufacturer?
Typically, if a lens is removable it is normally labeled with its true/actual (rounded) focal length, without any consideration for what it might be attached to (I don't know of any exceptions). That is true for the 18-55 kit lens you have as well; it is not adjusted for crop factor.
Conversely, if the lens is not removable the focal length is generally stated with the 35mm crop factor conversion applied.
All this confusion comes from the old "bad habit" to express field-of-view values not by themselves, but by the focal length that gives this field of view on a "standard" 24*36 film area.
Now that sensors come in all sizes (FF, cropped, M43, whatever), that habit fails miserably.
The focal length given with any lens means exactly that, its focal length, and doesn't care about the size of the sensor behind it, be it FF or cropped. And of course, with a given lens, if you have a smaller sensor, that sensor catches a smaller part of the image, thus giving a smaller field of view.
On the other hand, if a pre-digital book on image composition talks about a focal length, it most probably means the resulting field of view (assuming the FF 24*36 format), and has to be translated to the shorter focal length (divided by the crop factor) that gives the same field of view with a smaller sensor.