Pierre Roller (2000) "Dictionnaire encyclopédique des cépages" Hachette ISBN 2-01-236331-8 is an updated version* Galet, Pierre (2002) "Grape Varieties: A Study of Wine", Hachette Wine Library (Cassell), ISBN 0-304-36409-6 is a decent summary in English.
Pierre Roller (2000) "Dictionnaire encyclopédique des cépages" Hachette ISBN 2-01-236331-8 is an updated version* Galet, Pierre (2002) "Grape Varieties: A Study of Wine", Hachette Wine Library (Cassell), ISBN 0-304-36409-6 is a decent summary in English.