I've been lucky enough to get hold of a pre-release copy of Tristan Gooley's (The Natural Navigator) forthcoming book 'The Walker's Guide to Outdoor Clues and Signs'. It is a big beast but bursting with lots of fantastic facts about the great outdoors (and not just purely about navigation). I've done a more detailed blog page here>> http://austinlill.blogspot.co.uk/201...ues-signs.html
He's also recently joined Facebook too.
https://www.facebook.com/thenaturalnavigator?fref=ts