Thomas J. Perkins, who nurtured Silicon Valley’s venture capital industry into a force that later helped foster the growth of companies like Google and Amazon, died Tuesday night at his home in Marin County, Calif. He was 84.

His longtime assistant, Kathy Daly, said Mr. Perkins died after a prolonged illness, which she did not specify.

Mr. Perkins co-founded the venture capital firm Kleiner Perkins Caufield & Byers in 1972, at a time when parts of Silicon Valley were still fruit orchards. Mr. Perkins and his partners popularized a model of investment that involved putting small amounts of money into promising young start-ups in return for a stake in the companies, giving them advice and counsel to spur their growth.

Some of the investments turned into gigantic hits. Mr. Perkins had said that his favorite investment was Genentech, a biotechnology company that has since been acquired by Roche. Over time, Kleiner Perkins — and its home on Sand Hill Road in Menlo Park, Calif. — became a destination for other venture capitalists.