Author Lee Child wrote each Jack Reacher novel to be self-contained so that people can read them in any order they want. Alternatively, people can either read them in the order in which they were published or the internal chronological story order of Reacher's life.
To access a list of Jack Reacher novels in order of publication, readers can go to Lee Child's official website, select FAQ/Media on the right side of the toolbar at the top of the page, click on FAQ, and click on Can I Read the Novels Out of Order? The first novels published, in order, are "Killing Floor," "Die Trying," "Tripwire," "Running Blind" and "Echo Burning."
Reading the novels in the order of publication allows readers to become familiar with the Jack Reacher character before trying the prequels. Readers can also begin with the prequels and move forward through Reacher's life. The first prequel in chronological time is "The Enemy," which deals with Jack Reacher's time in the army as an officer in the military police. The novel that follows "The Enemy" is "The Affair," which goes into why Reacher leaves the army. After these two prequels, readers can continue with "Killing Floor" and read the rest of the novels in published order.