An important point the authors make is that printed and online services are not necessarily equivalent, and that the latter does not replace the former. The two modes of retrieval are complementary, and using an online file effectively often requires that a searcher know the structure of the associated printed version, if there is one. The key element in any information quest--electronic or printed--is a clearly thought-out problem, which can then be applied to an appropriate databank. The techniques of defining the problem, selecting valid terms, and choosing the right resource allow one to use either printed or electronic tools, or both in tandem.

Unlike some other recent texts, From CA to CAS Online does not dismiss the formidable array of printed searching tools that many chemists know and prefer. In-depth descriptions of Chemical Abstracts Service's (CAS) publications--Chemical Abstracts and its assorted indexes, CASSI, the Registry Handbooks, the Ring Systems Handbook--are accompanied by useful and fully illustrated sample searches. These serve to point out how much thought must be put into a search in order to get reasonably comprehensive results, as opposed to a quick look-up.

The added power and accessibility of online searching has focused attention on this medium in recent years, and Schulz and Georgy provide a useful overview of the most useful chemical databases available via STN, starting with Registry and CA, and proceeding through patents, CASREACT, MARPAT, Chemical Industry Notes, Beilstein, and Gmelin. They conclude with a helpful chapter comparing access to major CAS files on six different host systems.

While the STN interface allows one to search quickly at a basic level, learning to search dozens of different databases effectively is impractical for a researcher who has more important things to worry about. This is where Schulz' book comes in handy. Any chemist who does regular online searching would benefit from having this book next to the terminal. It summarizes the "big picture" of chemical information-seeking in both printed CA and online on STN. Consulting it beforehand could save considerable time and money that might otherwise be wasted in a hasty or inexact search.