“We shall in this book try to go in the footsteps of Paul. It will not be all easy traveling for any of us, to journey with this daring explorer of the Unseen; there is some steep hill-climbing, some scrambling over boulders, long flat tramps over the plain, and dangerous sea-journeys for anyone who will attempt really to follow the life of this man whose eager brain was ever ‘Voyaging on strange seas of thought/Alone!’ But, if you will … trudge by him till you really know him, you will have found for yourself one of the great companions of the world.” (From the Introduction)