It is a stretch to call Isaias Hellman the creator of modern California, as the author (a descendant) does, but the Los Angeles banker did have much to do with the late 19th- to early 20th-century economic surge in the city. We more often salute the Golden State’s politicians than its more worthy entrepreneurs, so this biography of financier Hellman is welcome. The poor Jewish immigrant not only founded the Farmers and Merchants Bank, he helped develop the interurban trolley system that tied L.A. and its sprawling environs, helped make The Los Angeles Times so influential, was involved in the state’s wine and early oil industries and assisted in the founding of USC. For the first time, we have the story of one of the coast’s major Jewish pioneers, like Adolph Sutro and Levi Strauss, and it’s told here in fine fashion.