Andrew raised the question of "the five books that have changed the way we think, or helped shape our own personal philosophy most", and I felt challenged. As I plunge recklessly into this subject (I was always one of these teachers who started a lesson in a spirit of adventure ...) I don't know if it'll come to five, but here goes:
The Myth of God Incarnate", edited by John Hick, was the first book of this type that I had read. It marked a return to serious reading after the brain-dead period of childbearing and opened up new avenues of thought. As did ...
The Go-Between God by John V Taylor, which I read shortly after spending three days with the author on a consultation entitled "Peacemaking in a Nuclear Age". I was so impressed by Bishop Taylor that I'd have read his shopping list at the time, but this book is covered in my orange highlighter, so keen was I to take it all in.
Shakespeare's "Hamlet". Studying this play at the age of 17 was the first time I'd become truly engaged with poetry/drama and I learned big chunks by heart - not merely for exam use, but because I wanted them as part of my soul.
The poems of Wilfred Owen. I actually read these for the first time in the programme for a performance of Britten's War Requiem - which, come to think of it, must have taken place soon after its composition. I was in S6 and had sat Higher English the year before; I was still studying the subject and yet this was the most modern poetry (1918!) I'd ever read. It was the start of a new life ...
The Scottish Prayer Book, 1929 vintage. I don't feel the need to use it in my worship now, but when I first came to it about 1970 it bowled me over. I was on the road to falling off my donkey four years later, and I can still remember the thrill of the beautiful language of the prayers and the sonority of the images. As a cradle Presbyterian who had turned her back on the church - and Christianity - before the music and the liturgy of the Episcopal church seduced me, I was amazed that anyone could own a copy of this magical collection.
There. I did reach five books. There may be more, but these have the cachet of being the spontaneously recalled items. Thanks for the idea, Andrew!