I have to disagree with Alceria. If this will be the only class you take this summer, and are doing nothing else and can devote yourself 100% to it for 6 weeks, you may learn more and retain more than if you take it along with 2 or 3 other big classes which compete for your time, or a job. If you can't devote yourself to it like this, consider auditing it instead and taking it for a grade when the opportunity next arises.