SAP's three-tiered architecture is the backbone of an R/3 infrastructure. It's what makes an R/3 system flexible, reliable, and open, all at the same time. It's also what makes locating underlying data, at times, so inherently difficult. For example, when you need several fields from a transaction for a report or an enhancement, you will probably need to find many of the transaction's tables and establish the links among them. Those links are often not obvious. This article shares 18 techniques the author has gathered and developed over time to locate such data, along with advice on which techniques to try first, and which to use only as a last resort.