The publication of a new law textbook just three days before the exam in a course given by its author has prompted quick sales of the book, an employee of the Harvard Book Store said yesterday.

"American Constitutional Law," by Lawrence H. Tribe '62, professor of Law, went on sale yesterday afternoon. The book store had sold ten copies of the 1200 page book within an hour of putting it on the shelves, the employee said.

"Eager law students have been calling every five minutes" to see if the book, which sells for $22.50, has arrived yet, the employee said.

Students in Tribe's constitutional law course, one of the largest courses in the Law School, have an eight-hour take-home exam that can be taken on either Thursday, Friday or Saturday.

Tribe said yesterday he had warned his class not to buy the book for the exam. "Because of its length and cost I couldn't expect them to read it," Tribe said. He added there was enough pressure on the students without having to read the book.

One second-year law student in the course who bought the book said yesterday it was more coherent than the lectures. "It has an excellent index which would be helpful during the take-home exam," he added.

Another second-year law student said yesterday he will not buy the book. "I do not know anyone who is planning to buy it for the exam," he said. "There is no need to read it if one absorbed the lectures."