Engineering has long been recognized as a key to the U.S. economy. Yet for more than 20 years, colleges of engineering have been warned that they are failing to keep their curricula and teaching methods relevant, threatening the profession and, by extension, the nation's economic prosperity. After a close-up look at 40 American engineering schools, the Carnegie Foundation for the Advancement of Teaching has released a new report on the matter, but the diagnosis is old news: A widespread emphasis on textbook-heavy theory over hands-on practice discourages many students and leaves the ones that remain unprepared for real-world problems. With the difficulty long known, why have solutions been so elusive? Among the reasons cited by college leaders: a faculty culture resistant to change, and perceived pressure from accreditors.