Your engine needs 5 things to start and run properly:
1) A battery with enough power to turn the engine over fast enough to start.
2) A good starter strong enough to turn the engine over fast enough to start.
3) A engine in good mechanical shape with the correct valve timing and compression.
4) Proper fuel air mixture delivered to engine by the carburetor or fuel injection system.
5) Proper spark of high enough voltage across good spark plugs. This spark must happen at the correct time.
Cars that won't start usually have either a fuel supply problem or a no spark problem. No spark can also be caused by a bad coil, rotor, distributor cap, electronic ignition module, pickup coil assembly, or wiring defect.