In a clumsy, roundabout opening, 13-year-old Chicano Juan Berna wows his 5th grade () classmates, in a ""what-did-you-do-this-summer"" session, with word of his exploits as a truck driver's helper. Then, however, things pick up. We hear (as we wouldn't in a classroom recital, but would in a fictional narrative) the story of Juan's family: how grandfather got a green card, permitting him to work in the US; how his oldest son, Juan's father, became a Field Boss; how he married Juan's Anglo-migrant (but illiterate) mother; how he was killed; how Juan's mother makes do; how Juan yearns for a bike; etc. Altogether: a relaxed, suggestive portrait of one barrio family. Then the Bernas clean up the yard of the Mystery Man next door (for a good, tactfully explained reason), and Pietro Verdi, a.k.a. Pete Green--a widower with a baby--enters their lives. Chiefly he'll take Juan along to the depot where he keeps his 18-wheel tractor unit: ""I do not own any trailer boxes . . . Mr. Mozzeri owns the trailers and warehouses. He hires me and leases my truck to hire produce all over Southern California."" And, in the course of the summer, Juan will travel from Stockton to Long Beach to pick up bananas; learn to shift the 13 gears, and then actually to drive; speak over the CB, and acquire a CB monniker, Kingpin; help Pete make daily, drudge-work pickups; and, in a stick-on climax, save Pete in an accident. Along with lots of trucking know-how (and some career guidance), there's much engaging interaction in the barrio--including a citizens' protest. Fourth-fifth grade in tenor and appearance--but all the way up in level of address.