Spare Parts begins and ends with footprints. In Lenny’s letters from boot camp, he described how scared he was standing on the yellow footprints all Marine recruits followed during training. Williams felt their call even then. For years, as Lenny completes training, as he visits home, as Williams grows older, he hears the call of the yellow footprints, which means he hears the call of the Marine Corps and following in his brother’s footsteps.

The subtitle of Spare Parts is“A Marine Reservist’s Journey From Campus to Combat in 38 Days.” Much of the book is about journey: the first journey follows the yellow footprints to the Marine Corps. After becoming a Marine, Lenny talks differently, walks differently, stares differently, and Williams imagines transforming himself as Lenny has. When Lenny visits home, he teaches Williams how to march, how to make his bed, how to wear his hair. He teaches Williams how to fight, and, after knocking down a bully, Williams gets his nickname “Buzz,” referring to his high and tight haircut: “That kid with the buzz cut can fight!” (xi).

But it’s after Lenny’s death that Williams begins to seriously think about following in his footsteps. When Big Ray, a former Marine at the gym where Williams works, reminds Williams of how far he has drifted from his childhood dream of joining the Marines, he goes to see the same recruiter Lenny had signed under.