I don't remember the author of this book.
The title/subtitle was something about mystery/secret, Delphi oracles... But since this was a translation, it is quite possible the original title is different.
The book was about strange things and coincidences in the world, hexagonal patterns... I read the book about 13 years ago.
Unfortunately, I do not remember much else and my online searches failed miserably.
I read it in my own language, Bulgarian, but I believe the original language is English.
The author's name was plain - Robert, Tom - something like that. I do not remember much of the book itself but it was telling about finding hexagonal patterns everywhere in nature and lots of other stuff. That is why I would like to reread it - because I have forgotten most of it.
Hopefully, someone here might have read it. :)
PS. It is not The Sirius Mystery by Robert Temple and I don't remember any alien references in the book itself.
The book was of "normal" size - i.e., around 300 pages more or less.
PPS. The book is not famous, nor the author.