Didnt see a lot of reviews for it so i thought I will write one. To put it very simply: Its Macguyver meets Indiana Jones. The end. I read on Wikipedia that it can be described as "Matlock meets Jack Ryan", but i see less of that at the start. If you have a fix for stuff like Adventures of Tintin, Batman by Denny O'Neil & Neal Adams but want a bit more mature story telling and some research like in Hugo Pratt's Corto Maltese, but not that academic, then pick this one up. If you like historical mysterys like Da vinci code, then pick thisup. Legendary Musings of Professor
Munekata? Pick this up.

Urasawa teams up with a Historian (because a lot of it is pretty well researched) and a writer of Golgo 13 to write the globe spanning adventures of Taichi Hiraga Keaton.

Usually Urasawa stories are long form where the plot hits the ground running, like in Pluto, Monster, etc. But in Master Keaton you don't have an overarching plot, just the interesting adventures of an ex-special forces university lecturer who freelances for LLoyd's of London to make ends meet.
This allows for the creators to tell a diverse breadth of stories, from negotiating a hostage rescue in England, to discovering shipwrecked treasures by the coast of Greece, to meeting ex-German nobility in Berlin. Not all of them are action packed, some wax philosophical, some are more mystery oriented, but they are all pretty damn engrossing.

So far I am at volume 3 and I am not sure if there is a plot that will eventually get shown but you can say skip volumes and still not miss out much so long as you read volume 1 to get acquainted with the characters. There are few recurring ones, Keaton's family basically, while the rest are only relevant for the story that is being told, making it one of the few Urasawa works, to my knowledge, that you can just pick up at any random point and have a good time.