With “Justice” out of the running this year and Life Sciences 1a coming in third, Economics 10: “Principles of Economics” took the lead as the most-enrolled course this semester.

The mega-course taught by campus legend N. Gregory Mankiw will introduce 731 students to classical economic theory, a marginal drop from the 776 students it had last year.

“I am delighted that so many students are choosing to take Ec 10,” Mankiw wrote in an emailed statement, adding that he wished he could enroll every single freshman—with the exception of students who are already prepared for more advanced coursework—in the course.

But what’s rising to be a formidable foe to the market leader is Computer Science 50: “Introduction to Computer Science I”—not that Ec 10 disapproves of competition.

An increasingly trendy course with a project fair and even its own logo, CS 50 drew 651 students this semester, a 32 percent increase in enrollment since last fall when 494 students took the course.

“We’re thrilled, both as a course and as a department and school,” lecturer David J. Malan ’99 wrote in an emailed statement.

The jump continues the multi-year rise in enrollment for the course. Since the fall of 2007 when Malan took the helm of the class, course enrollment has increased by 131 percent.

“At Harvard, the person who gets the credit is David Malan,” Computer Science Professor Margo I. Seltzer ’83 told the Crimson last May. “He turned CS50 into a class with a real community.”

Life Sciences 1a: “An Integrated Introduction to the Life Sciences: Chemistry, Molecular Biology, and Cell Biology,” a requirement for most subsequent life science courses, had the third highest enrollment with 517 students.

The six newly-designed General Education courses also had a strong showing on study card day, with Ethical Reasoning 30: “The Just World” leading the pack with 121 enrollees.

Ethical Reasoning 30 was so popular that two additional discussion sections were added after enrollment figures came in, according to the course website, boosting the number of sections in the course to seven.

Culture and Belief 50: “The European Postwar: Literature, Film, Politics” and United States in the World 36: “Innovation and Entrepreneurship: American Experience in Comparative Perspective” also did well, with Culture and Belief 50 drawing 109 students and United States in the World 36 drawing 96 enrollees.

Enrollment in an existing Gen Ed course, Culture and Belief 22: “Concepts of the Hero in Classical Greek Civilization,” skyrocketed, jumping from 68 enrollees last fall to 224 this semester.

On the first day of shopping period, Professor of Classical Greek Literature Gregory Nagy said he thought that the high turnout to his course was due to “a genuine hunger for understanding classical civilization at a time when moral problems seem to overwhelm us.”

Nagy said he was encouraged by the interest in his course “at a time when science is very eminent as a speciality.”

“The numbers that we’re now getting are reflective of the kind of interest Harvard students still have in the humanities,” Nagy said. “Scientists too have hunger for the humanities.”

On the other hand, Science of the Physical Universe 27: “Science and Cooking: From Haute Cuisine to Soft Matter Science” saw a dip in enrollment, drawing only 175 students this fall after enrolling 273 students last fall, the first semester the course was offered.

Last year, Ethical Reasoning 22: “Justice” took the lead with 800 students, but the popular philosophy course is not offered this year.

Initial enrollment figures could change over the course of the semester as students add and drop classes.

—Staff writer Rebecca D. Robbins can be reached at rrobbins@college.harvard.edu.