Sergey Brin Is Back in the Trenches at Google

Google co-founder Sergey Brin is back at work. The multibillionaire has been visiting the tech giant's Mountain View, Calif., offices in recent months generally three to four days a week, working alongside researchers as they push to develop the company's next large artificial-intelligence system. WSJ: Brin participated in meetings about AI at Google's offices late last year, but the frequency and intensity of his involvement has picked up, said people familiar with the matter. His new stance is