I just finished Silent Invasion: The Pennsylvania UFO-Bigfoot Casebook by Stan Gordon. I had it sitting around in my Abebooks basket for ages, and can't remember where I heard about it, although I should think it was either from Where the Footprints End or Truth-Proof volume whatever. It is essentially a chronological listing of an astonishing array of UFO and bigfoot encounters in Pennsylvania from 1972 to 1974. There are some short chapters on the author's thoughts on what was going on (he investigated many of the incidents himself) and leans towards a paranormal interpretation, with so much high strangeness surrounding the bigfoot encounters, such as instantly disappearing bigfoot, partially invisible bigfoot, bigfoot holding a glowing light etc. A great read, if somewhat repetitive at times. It made me wonder where such weird outbreaks might have gone on more recently (not necessarily bigfoot-UFO, but sudden condensed flurries of much-witnessed strangeness in a given area).