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of 2.10 A as being typical of neutral sp3-hybridized nitrogen atoms in macrocyclic high-spin nickel complexes (see ref 7 and 1 I), then an optimum hole size of -4.25 A is predicted for nickel(l1). This is larger than that of 4.13 A determined by X-ray for free 15-02N2 in a flat conformation (McPartlin, M.; Tasker, P. A.; Trotter, J., unpublished results) and supports the postulate that the hole size of 16-02N2 is the one of best fit for the present series of ligands.

Photocycloadditions of biacetyl to norbornene and syn-7-methyl-and íyn-7-íerr-butylnorbornene have been observed. The stereochemistry and quenching rates are consistent with increasing steric hindrance to the exo face of norbornene as the syn-7-substituent changes from H to CH3 to f-C4H9. The intramolecular analogue of these reactions was studied via 1-(5'-norbomene-2'-yl)-1,2-propanedione, which gave an oxetane on direct irradiation at 300 or 430 nm or on benzophenone-sensitized addition. The direct irradiation reactions are believed to proceed via singlet states as evidenced by estimated lifetimes derived from quenching by 7V,A7-dimethylaniline. The effective molarity (EM) for these reactions is estimated to be >101 234 (St) and >105 (T,).

Reviews 147 simultaneous bombings against Western housing compounds. However, the authors also reason that heightened security is insufficient to deal with the problem in the long term and that the best antidote to domestic instability is to engage more Saudi Arabians in the political arena. They encourage Saudi leaders to pursue a broad program of reform that deals with political, social, economic, and religious challenges. The discussion of Islamic extremism and the need for reform will likely be most interesting for those curious about the connection between security and domestic politics in Saudi Arabia. Unfortunately, this discussion is also the book's most serious analytical weakness. Although Cordesman and Obaid quietly exhort Saudi leaders to do more in dealing with both militancy and reform, the sections that deal with these issues too often come across as an apologia for steps already taken rather than a critical or substantive discussion of what should be done next. Since the first outbreak of domestic militancy in Saudi Arabia, analysts in the kingdom itself, as well as in Europe and the United States, have discussed the need for reform in considerable detail. National Security in Saudi Arabia fails to engage any of those earlier works and, regrettably, contributes little that is new to the discussion. The book's strength lies in its detailed discussion of military and security apparatuses and capabilities, which will be of significant interest to defense and policy analysts.

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