A first-hand look at U.S. corporate cultures

By Lisa Von Ahn

NEW YORK (Reuters) - It's not unheard of for journalists to go undercover to blow the lid off harsh conditions or wrongdoing, but freelance writer Alex Frankel had something else in mind when he infiltrated big U.S. corporations as a customer-facing employee.

He wanted to know what it was like to work at these companies and how they assimilated new hires, he writes in his new book, "Punching In" (Collins Business, $24.95).

Frankel got his answers by serving coffee at Starbucks, working the men's department at Gap, delivering packages for United Parcel Service, selling computers at an Apple Store and training to become a manager at Enterprise Rent-a-Car.

Frankel had many good things to say about UPS (UPS.N: Quote, Profile, Research, Stock Buzz), where he temped during the Christmas rush.

The work was hard, and at times he wanted to quit. But as he brought holiday gifts to families, he was thrilled to be part of something important.

"On the back end, the computer systems were as high tech as they come," he wrote, "and on the front end you could also argue that the humans were as human as they come."

Frankel also appreciated Apple (AAPL.O: Quote, Profile, Research, Stock Buzz), which hires people who are already fans of its products.

"Workers don't seem to be working or selling, just hanging out and dispensing advice."