Brittain-Catlin begins by observing that the Cayman Islands are the 5th largest banking center in the world, with over $700 billion in assets.
These assets, however, are largely not physically held on the island - simply notations in accounting books for the purposes of reducing or eliminating taxes. Corporations taking advantage of this include GM, ExxonMobil, Ford, IBM, Wal-Mart, G.E. (reduced its 27% '99 tax rate to 16% in '03), Citigroup (saved $778 million in '03 taxes), Apple, Enron, Halliburton, Tyco, Global Crossing, Long Term Capital Management, Global Crossing, and Enron.
"Transfer-pricing" manipulation is the main tax-avoidance mechanism afforded by offshoring. This involves corporations maximizing overseas production profits in a non-taxable offshore subsidiary.
Unfortunately, Brittain-Catlin seeming dwells forever on his basic facts, and even spends considerable time exploring the philosophy of Kant. (I tried reading Kant long ago - Brittain-Catlin's version was no more interesting.)