Quick excerpt from the ad copy:
Volume 4 containing Cervon notebooks 9, 10 and 11, composed from 1967 through 1969 - 424 pages
SPECIAL: For one week only, from now until Friday, April 17, 2009 (no exceptions), in order to provide an opportunity for you to request the same number book you received for Volumes 1, 2 and 3, you may request that number for Volume 4. These requests will be honored in the order in which they are received. If ordering online, make sure to enter your number request in the customer comments section of the online order form. If ordering by telephone, make your request known to our customer service representative. Credit cards will not be charged until your order ships.
All the details at the link above.