Wayne, with out more information, year, make, model,engine, transmission,any recent repairs, previous issues, is the security light on, etc.. I would suggest you have the truck scanned for trouble codes, which could direct you to the fault. If no codes present check the attached links for engine cranks no start diagnosing. Good luck.
I hope this helped you out, if so let me know by pressing the helpful button.
http://troubleshootmyvehicle.com/ford/4.6L-5.4L/how-to-test-a-no-start-condition-1#2
http://www.ifitjams.com/starting.htm