Abstract: Method of hydraulic fracturing of a subterranean formation comprising drilling a deviated wellbore in a direction parallel to a desired fracture direction, and supplying fracturing fluid through the wellbore to the formation. The average net pressure on the fluid is maximized in a fracture formed in the formation by pumping the fracturing fluid at a maximum rate, and by using a high viscosity fracturing fluid. Maximization of the average net pressure acts to extend the fracture in a direction parallel to the direction of the wellbore. The amount of the extension of the fracture is a function of the ratio of the average net pressure to the horizontal stress difference, whereby the higher the ratio, the greater the amount of the extension.