84, Char Cross Road
by Helene Hanff
My 'daughter' ordered this from a used book store and I could not resist it.  It's only 100pp., but I had to take a bit at a tme to make it last...you don't eat the whole cake at once.
This delightful book is simplyt the letters between a NY writer and and an English clerk at a bookstore. They begin in 1949. [pub. 1970] Best described as a wonderful, witty, celebration of intellect and friendship. 
Also, just re-read the Preface to John Bright's The Kingdom of God, , which alone is worth the price of the book [I don't have a clue what it costs these days from a used book store.]