Observations Made During a Voyage Round the World is Johann Reinhold Forster's systematic account of the scientific and ethnological results of the second voyage of James Cook. Forster, a former pastor who had become a Fellow of the Royal Society after writing several papers on natural history, and his son Georg had accompanied James Cook as naturalists on board of HMS Resolution. Originally, it had been planned that Forster's account should appear together with Cook's "narrative" of the voyage, but after lengthy arguments between Forster and John Montagu, 4th Earl of Sandwich, the First Lord of the Admiralty, Georg went ahead and published his own narrative instead in 1777, A Voyage Round the World. Observations then appeared in 1778, financed by subscriptions. It was translated into several European languages, including a German translation by Georg Forster.
The book discusses geography, oceanography, ethnology, and anthropology of the natural phenomena, places and people encountered during the voyage. It was praised in contemporary reviews and influenced philosophers like Johann Gottfried Herder. On the other hand, it was dismissed by Forster's opponent William Wales and the later Cook scholar John Beaglehole, and for a long time was not given much recognition. As a book containing results obtained after first hand observation, geographers including David Stoddart more recently considered it among the first works of modern geography.