Vivek Wadhwa,

Wharton Digital Press,

106 pages, $15.99

Vivek Wadhwa's new book, "The Immigrant Exodus," is admirably short, yet he packs it with righteous fury.

The United States, he points out, has one of the greatest assets a nation can have: people yearn to live here. Chinese students, Indian doctors and French financiers flock to its shores. Such a nation, one that can attract the cleverest people in the world, can innovate and prosper indefinitely.

Unless it does what the United States has done since Sept. 11, 2001, which is to make the immigration process so slow, unpredictable and unpleasant that migrants stay away.

Wadhwa's findings are alarming. In a survey, he found that most Indian and Chinese students in the United States expect problems in obtaining a work visa, regardless of demand for their skills. An unprecedented number plan to go home. Wadhwa believes that immigration policy has halted the surge in high-tech firms founded by immigrants.

"The Immigrant Exodus" is packed with examples of opportunities squandered for want of a visa. Hardik Desai, for example, persuaded investors to put $300,000 into his start-up, which made diagnostic technology. But he could not persuade the immigration authorities to let him work for his own company without proving that it could pay his salary for a long time -- something almost no new firm can prove. So he had to shut it down.

Wadhwa, who is of Indian origin, moved to the United States from Australia in the days when it was easy. Working as a computer scientist, he received a green card in 18 months and founded two companies. He laments that, if the conditions had been as they are now, "I would have been a fool to leave Australia."

By locking out foreign talent, the United States has "blocked the flow of [its] very lifeblood," he argues in this wise and powerful tract. Yet the problem is simple to solve. Wadhwa lays out a seven-point plan that can be summarized in three words: Let them in.