Redmond and Smith reveal how the development of a continent-wide advance warning system against attack by missiles and manned aircraft set the stage for 1960's computing development. SAGE's design introduced concepts related to mass data processing that would later make personal and business computing a reality.

1."It worked!" -- 2. The beginning of the beginning -- 3. ADSEC -- 4. Valley's discovery -- 5. Managerial misgivings vs. technical accomplishments -- 6. The problem of "internal storage" -- 7. Project whirlwind's perspectives on computer R & D and air traffic control -- 8. Do it right, cut off, or temporize? -- 9. The Bedford tests -- 10. Project Charles -- 11. Lincoln laboratory -- 12. Organizing the tasks that faced Division 6 -- 13. Planning the air defense computer -- 14. The memory test computer -- 15. IBM and the air defense challenge -- 16. Collaborating on the XD-1 -- 17. Bringing IBM up to speed -- 18. Tight schedules, slippage, and project grind -- 19. Adjustments and triumphs -- 20. Slippage, the XD-1, and the XD-2 -- 21. Technical memorandum 20 : the pattern for the future system -- 22. The Air Force decides -- 23. National policy decisions -- 24. Implementing TM20 : "Who's in charge?" -- 25. The 1953 Cape Cod system -- 26. Further R & D planning and the 1954 Cape Cod system -- 27. Problems with manpower, computer programs, and intercept testing -- 28. Design progress and administrative reorganizing -- 29. Checking out the ESS -- 30. The problem : weapons integration and systems engineering -- 31. The solution : MITRE -- 32. Epilogue.