There's one in the completed listings showing measurements of 14 x 13.5.Jeez, the guy has the information right in front of him on the receipt. Anyone who bids thinking they're getting a Willis is going to be PO'd.
The receipt is dated 1998, not 1988, and it's actually for that bag, which is a Beekman Computer Bag, style 5299, similar to the 5266 Beekman Brief and probably from around 1997-98. I don't have anything else in my files on it, not even measurements, or at least I didn't until I saw that listing. Since laptop computers from the late 90s were pretty large, it would have to be big enough to handle something with a 15 or 16-inch screen at least, and at least an inch thick or more. So it must be around 16x14 inches but that's just a guess.
But it AIN'T no Willis, Willis!
http://www.ebay.com/itm/Vintage-Coa...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557