The birth of the Microprocessor in the great digital calculator race, or the Story of how the Japanese electronic calculator Busicom 141-PF spurred micro-computer innovation and led Intel's to its eventual fortune through the 4004 line of ICs (chips).
Interesting is the claim of Wayne Pickette that it was he, at the age of 20, working for Intel in the Spring of 1970, who was the real inventor of the 4004 but that he was cut out of the credit and the official story of it's creation. [2]
[1] Busicom 141-PF and Intel 4004:
http://www.vintagecalculators.com/html/busicom_141-pf_and_intel_4004.html
[2] Wayne Pickette inventor of the Intel 4004 and Intel’s Forgotten Past: https://plus.google.com/u/0/+AssadEbrahim/posts/E991WE5RhLp