Malkin travelled in South Wales (1803) and in 1804 published a book which is far better known in its second, two-volume, ed., The Scenery, Antiquities, and Biography of South Wales. This is by far the best of the old travel-books on South Wales - acute and interesting in its observation, usually tolerant in its judgements, with a substantial knowledge of Welsh history and (up to a point) of Welsh literature.