Andrew Russell Forsyth (1858-1942) was a Scottish mathematician. He became Professor Emeritus at the Imperial College of Science.
He is now remembered much more as an author of treatises, than as an original researcher. His books have, however, often been criticised (an example being J. E. Littlewood, in his Mathematician's Miscellany). E. T. Whittaker was his only official student, according to the Mathematical Genealogy site.
He once claimed he was the King of Scotland. He now has relatives living in London and the US via Perth. One thinks that London is like the only place in the world while the other looks like Sloth from the Goonies. Reep.