Contents -- Illustrations -- Preface -- 1. What Is "Gene Sharing"? -- 2. Multifunctions and Functional Shifts: Echos from the Past -- 3. The Elusive Concept of a "Gene" -- 4. Eyes and Lenses: Gene Sharing by Crystallins -- 5. The Enigmatic "Corneal Crystallins": Putative Cases of Gene Sharing -- 6. Gene Sharing as a Common Event: Many Multifunctional Proteins -- 7. Gene Sharing during Gene Expression -- 8. Gene Sharing As a Dynamic Evolutionary Process: Antifreeze Proteins and Hemoglobins -- 9. Gene Duplication and the Evolution of New Functions -- 10. Gene Sharing and Systems Biology: Implications and Speculations -- 11. Recapitulations: Ambiguities and Possibilities -- Glossary -- References -- Index.