There is only one book that I have read more than twice. I have just finished a third reading of 'Teachers of Gurdjieff' by Rafael Lefort. I first came across an original 1966 HB copy of this book in my local library when I was in my early 20s. It was the first book that I read twice, whilst still in my early 20s.
I recently found a 1st edition 1966 HB copy exactly as I had first read it those many years before. It was a pivotal book for me, and did indeed change the direction of where I was heading.
'Why take this road to London when it leads to Llandudno?' ( I paraphrase!)