Nairobi, Nov. 15 -- Here's what Nashon Omondi, the CEO of HSC Systems, remembers about his childhood: His late dad being tough on his brother. Being the only surviving son in a polygamous household. The food. Oh, how plentiful it was-never mind his where-does-it-all-go appetite. He remembers, too, his dad leaving for Nairobi to work, what they call 'Pango'. "When dad came back home, each of the wives would bring food," he says. "Often I was the only boy around, and I enjoyed the most." His dad is long gone, but it's like he never left. Presence, after all, is most keenly felt in absence.

Now he is a father himself, and he has learned to hold his childhood up to the light and separate out the derisions and elisions, rolling his eyes at th...