This book is advertised as “continuing the tradition of Robert A. Heinlein… reads like an original by the late grand master.” I’m no expert on Heinlein, but that seems true (middle-period Heinlein, without the later pedagogical discussions of government, sex, and religion.)
Scalzi starts with foreseeable technology, briefly explained, and then goes far beyond, allowing his characters to accept it all with a shrug. What Scalzi wants the reader to know is often provided by the characters directly hearing or reading an explanation. The main character talks directly to the reader a couple times.
Today’s editors say this is old fashioned and readers will hate it. Ha! This book is very popular. Take that! editors.
The characters share an optimistic outlook and a wise-cracking sense of humor. They are ready to take a one-way trip as soldiers in a space war based on very little information, but without regret. This type of character does remind me of Heinlein. Also like Heinlein, in Part I the characters have sex for fun (without being pornographic) and the women have remarkable libidos.
Part I is fun with Scalzi’s universe. The war promised in the title arrives in Part II (and the sex disappears). Quite the opposite of Star Trek, the characters’ “job is to go meet strange new people and cultures, and kill [them] as quickly as we possibly can.” The humans aren’t especially noble, and while a friendly alien race is mentioned, generally everyone wants to kill everyone else to acquire worlds to colonize. Apparently, one battle on each planet is all that is needed, so the characters see many different aliens, and fight and die in a many different ways. The f-bomb is used a lot.
Battle scenes have never been my favorite reading, so I skim through them in most books. But I read Scalzi’s battles; they are not overly long and not simply gore fests designed to pack the book with pages. In addition to presenting varied action, due to the large variety of alien and human opponents, the battles contribute to the story. Part III delivers depth to relationships and to the war: some planets do require more than one battle.
While this is the first book in a series, there is an ending to the story. Wikipedia says there are a total of eight books set in this universe.
What others are saying
Old Man’s War is highly ranked on Amazon with 4.5 stars from reader reviews, generally liked as a fun space opera. Those who didn’t like it found the war unexplained and pointless, and noticed that the first and second halves of the book were quite different in tone and topic, or didn’t relate to the characters. True, but most readers aren’t turned off by that.