The book is again available by the miracle of modern technology, both as a free download and as a print-on-demand volume from the British Library. I came across this lovely book by chance - I was researching Leslie as a previous owner of my grandfather's house, Riverside in Wallingford.
The picture shows G.D. Leslie in his own punt, built in Maidenhead where, Leslie claimed, the best punts came from. The book is a treasure-trove of punting technique, river lore, boating advice and rants on the steamboat menace. More over the next few days.