OK, WOW! For avid Halloween paper ephemera collectors, seeing this listing should cause your hearts to race and your sphincters to seize. Seeing this quality listing amongst so much eBay dreck made my day. This is certainly the best listing I've seen come along in well over a year.
Completing a set of customized Dennison Bogie Book envelopes or enclosures is high on my list. They surface so rarely they warrant an RSIN of 1, except for the 1919 enclosure that has been assigned a 2. (I am proud to own enclosures for 1909, 1914, 1915, 1917 and 1919. I have never seen enclosures for any of the other years Dennison Bogie Books were produced so cannot even be sure they exist. You can see these extant enclosures in my third edition.) From the ones I do own, this 1915 enclosure is the most cleverly designed and memorable of all the others put together. This is the ONE to own. Less interesting by comparison is the actual 1915 Bogie Book itself. This issue is not easy to find and the condition seems to be acceptable. I'm glad the seller included a shot of the Bogie inside its enclosure to show the cleverness with which this was produced. The guide value for the enclosure alone is $500, but there was only a single data point to support that specific valuation. In my view, the sky's the limit, so I'll be buckled in watching where this listing ends.
08/23 Update: The air wasn't too choppy. Guide value for both items is $775 and it ended at $838. I feel the buyer got a very good deal overall considering the rarity of the enclosure.