The BLS Library has other Sum & Substance CD-ROMs on constitutional law, federal income tax, and legal research. They are all located in the AV room 111 on the ground floor level next to the reference desk. Students can check them out for a 48 hour period, with renewals. It is possible that the one you want may be checked out. If so, stop by the reference or the circulation desk and request a staff person place a hold on the item. Then you will be notified when the item has been returned, and you will be next in line for it.
Law student who are iPhone users can purchase some titles from the Sum & Substance series from the App Store. Currently, the following titles are available: contracts, criminal law, constitutional law, criminal procedure, and real property. Prices range from $49.99 to $59.99. See details at this link.