In one of the largest grants it has ever made to a single school system, the Bill and Melinda Gates Foundation has awarded $21 million to the Chicago Public Schools to establish a more rigorous high school curriculum, boost graduation rates, and better prepare students for college.

The money is a crucial element of the district's so-called "transformation project," a push by the nation's third-largest school system to cut high-school dropout rates and improve the fortunes of students who do go on to college.

The $21 million figure is the second-largest total that Microsoft Chairman Bill Gates' foundation has awarded in a single grant to a school district. In 2000, the Gates Foundation awarded $26 million to the Seattle Public Schools.

"The impact of this grant will be long-lasting," Mayor Richard Daley said April 17 in an announcement at Crane High School, one of 14 high schools that initially will be targeted for a new core curriculum. The district has 93 high schools in all.

Only 54 percent of freshmen in the district eventually receive a high school diploma, and many who make it to college require remedial classes to catch up, a study by the Consortium on Chicago School Research at the University of Chicago found.

Often, too little attention is given to providing students with a rigorous curriculum, leading to poor preparedness for college and high dropout rates, said Tom Vander Ark, executive director of education for the Gates Foundation.

A primary goal of the grant is to align the district's curriculum from school to school. One problem with Chicago's current approach is that, from high school to high school, and even from grade to grade within high schools, students encounter different textbooks, standards, and systems of assessment. These different curricula often overlap or leave out key elements from one grade to the next, officials said.

Each school to benefit from the grant will choose from among two or three carefully researched instructional programs in English, math, and science. Each program will combine print and electronic resources to engage, stimulate, and challenge students, officials said. For instance, schools will be able to choose either Agile Mind or Carnegie Learning's Cognitive Tutor for their math curriculum.

These curricula will be aligned, officials said, so that if a student completes ninth grade using Agile Mind in one school, then transfers to another school using Cognitive Tutor, he or she will still be at the same point in the curriculum, even though the instructional strategies for each program might differ.

Professional development is another important part of the initiative. Instead of offering vague, general training, all professional development will focus on deploying the instructional strategies of each curriculum program in question, officials said.

In addition "every teacher in this program will have a laptop [with an] internet connection," said Angus Mairs, assistant director for the district's Office of Planning and Development. Getting laptops into the hands of teachers, and "allowing them to experiment," is the starting point for leveraging technology in the classroom, he said.