Born in London, England, Harper wrote self-illustrated travel books, including those exploring the regions, roads, coastlines, literary connections, and old inns of Britain.

Aside from the some 170 topographical works, he wrote a books on drawing and its techniques, including English Pen Artists of To-day (1892) and A Practical Handbook of Drawing for Modern Methods of Reproduction (1894), and, as an anti-feminist polemic, Revolted Woman; past, present, and to come (1894), and a satirical novel, Hearts Do Not Break: a Tale of the Lower Slopes (1896), attacking logrolling among the London literary set.

R. E. D. Sketchley's English Book-Illustration of To-Day (1903) characterised Harper's travel books as "… written and drawn with spirited observation.

It has reticence and justness of expression that would not serve in relating tales of the road, but which, together with a sense of colour and of what is pictorial, combine to form an effective and frequently distinctive style of illustration".

N. W. Webster's article "The English traveller"' (1974) describes him as "more a capable draughtsman than a creative artist, although his books would lose much without his delightful sketches".