Robert Half International Inc. (NYSE: RHI) shares surged 15.8% to $29.91 Thursday on strong quarterly earnings. Volume for the stock closed in on five million shares, or better than triple its daily average.

The staffing solutions company, based out of Menlo Park, Calif., put out a press release July 20 stating that, for the quarter ended June 30, 2011, net income was $36.4 million or $.25 per share, on revenues of $938.0 million. Net income for the prior year’s second quarter was $12.2 million or $.08 per share, on revenues of $769.1 million.

Robert Half CEO Harold Messmer Jr., was quoted in the release as saying, “This is the fifth consecutive quarter we have reported accelerating year-over-year growth rates for our consolidated revenues. Second-quarter revenues increased 22% from one year ago, and second-quarter income per share tripled from the year-ago period.

Messmer continued, “We saw broad-based, improving demand for our professional staffing services and Protiviti both in North America and abroad. Our permanent placement and technology staffing divisions were particularly strong. The pricing environment also continued to improve during the quarter, which contributed to higher gross margins.”

Founded in 1948, Robert Half International Inc., the world’s first and largest specialized staffing firm, is a recognized leader in professional consulting and staffing services.