Robotech is pure space opera which is heavy on a "love conquers all" theme. There's some lip service paid to how people end up out in space or flying planes that turn into giant robots, but the real reason is effectively "magic." Magic in the form of "protoculture" in the case of Robotech, a substance that does strange things to people's minds as well as enabling crazy technological advances. Perhaps "protoculture" even has an awareness and agenda of its own. I've labeled this post science fiction because that's how Robotech is categorized when you go looking for the books or videos, but don't be fooled - it's an epic fantasy, with all the romance/tragedy/adventure that implies.
That's not to say, however, that Robotech uses mystical "protoculture" solely to manufacture happy endings. The initial alien attack against humanity doesn't end with humans beating back the assault. Not all the star-crossed lovers get a perfect happy ending. Earth is in pretty bad shape, humans and aliens have to learn to live together, and later on the planet ends up conquered by yet another alien race. People die, lots of them, including a few that the reader knows pretty well. By the time the series wraps up with The End of the Circle there has been plenty of good news, but the journey is certainly not all roses and rainbows.
The Robotech novels are roughly divided into four sections: the Macross Saga, the Sentinels, the war with the Robotech Masters, and the Invid Invasion. Three of those correspond to the three seasons of the television series; the fourth, the Sentinels, was going to be a sequel television series but never made it to air. Then you have three novels that fill in gaps between the four major parts, and The End of the Circle that takes the story beyond the various TV series timelines to wrap it all up. (That last is specific to the novels, since the animation went another way with Robotech: The Shadow Chronicles. I much prefer the story of the novels to the animation.) If that sounds like a lot of reading, you're right: 21 books in all. Though many are fairly short as novels go, that's still a whole lot of words. A reader has to really enjoy the universe and characters to make it all the way through that kind of verbiage.
Those three "fill in the gaps" novels were new to me, as they were written after the rest. By the time those three came out, I'd already finished the rest of the series, and at the time I never even looked for additions. Of course, that was 25 years ago, so my memory of the details is hazy at best. I'd been thinking about re-reading the series, curious as to whether I would still enjoy it a couple of decades later. When I saw the books were available on Amazon for the Kindle, that gave me the excuse I was looking for to read the whole series in chronological order. (Well, all but one were e-books. For arcane reasons of publication rights, The Masters' Gambit is only available in dead-tree format, and out of print to boot. Had to order that one from a used book store, and it cost nearly as much as the entire rest of the series combined!)
Those quotation marks around the author's name up above are there because there was no actual Jack McKinney - the name is a pseudonym used by American authors James Luceno and Brian Daley. I had no idea of this when I first read the books, of course. As a sci-fi obsessed teenager, I didn't much care where the stories came from!
Novelization of television is a tricky thing. You have to describe in words what people simply absorb by watching, while still capturing whatever tension and emotion the sound and visuals evoke. You also get the opportunity to expand on things that didn't make it on screen for whatever reason (often time or budget constraints). And you need to find a way to explain some of the more absurd things that happen; on screen it might go by quickly, but in writing there's always time to stop and say "wait a minute, they did what?" (Inasmuch as explanations are possible...some of the scripting was just too absurd to really explain.) No one is perfect, but I think the authors did an outstanding job on all those fronts in these novels. I read them before I'd watched the television series. When I finally did see some of it (never did watch the entire thing), I mostly felt underwhelmed, because I felt I knew so much more from the books than what was shown on screen. This is particularly true in the character motivations and internal struggles. There are a lot of insecurities that are explicitly laid out in the novels which humanize the characters - Rick in particular - that didn't really come across on screen.
Those characters are key to the Robotech franchise, at least for me. Don't get me wrong, it's not like the latest type of giant robot or the fate of invading alien armies do nothing for me...wouldn't be reading this series otherwise. But honestly, I cared at least as much (maybe more) about what happened to Rick Hunter or Dana Sterling or Scott Bernard as those big-picture questions. Unlike a lot of stories that started as cartoons, these characters have some depth and history as you work your way through the series. I especially appreciate that some pretty important people die off - the whole series basically takes place during wartime, and not everyone makes it through. Losing some people along the way gives those who remain that much more depth.
I should also mention Macross here, since Robotech and Macross are two offshoots of the same initial story. They have transforming space fighters and giant fortresses in common, and of course the original series characters. However, they go very different directions past that. Robotech focuses on the power of protoculture (a tangible thing derived from weird plants), the various factions and races fighting over it, and how it changes everyone and everything it touches. Macross treats protoculture as a concept based on ancient civilizations, and power largely comes from heroes finding strength within (often by singing). In my opinion, Robotech is the better story, but you really need to read the novels to get that story. Based on all the watching I've done, I'd rate Macross as the better anime series. So if you're looking for something to watch, go with Macross; for something to read, pick Robotech.
Having now read the Robotech novels twice, I feel qualified to say that the series ages well. The first time around, my teenage self was mostly interested in the giant battles and major events directing the epic sweep of history through the series. During this second reading as an adult, I found myself much more interested in the individuals at the heart of the story, and how the authors tied together the various phases of the story into a coherent whole. Regardless of where you are in life, the series is certainly aimed at a niche audience that loves epic fantastic adventure, futuristic mecha battles, and romantic underdog victories. If you fit that description, then you'll get plenty of enjoyment out of the Robotech novels.
I should also mention Macross here, since Robotech and Macross are two offshoots of the same initial story. They have transforming space fighters and giant fortresses in common, and of course the original series characters. However, they go very different directions past that. Robotech focuses on the power of protoculture (a tangible thing derived from weird plants), the various factions and races fighting over it, and how it changes everyone and everything it touches. Macross treats protoculture as a concept based on ancient civilizations, and power largely comes from heroes finding strength within (often by singing). In my opinion, Robotech is the better story, but you really need to read the novels to get that story. Based on all the watching I've done, I'd rate Macross as the better anime series. So if you're looking for something to watch, go with Macross; for something to read, pick Robotech.
Having now read the Robotech novels twice, I feel qualified to say that the series ages well. The first time around, my teenage self was mostly interested in the giant battles and major events directing the epic sweep of history through the series. During this second reading as an adult, I found myself much more interested in the individuals at the heart of the story, and how the authors tied together the various phases of the story into a coherent whole. Regardless of where you are in life, the series is certainly aimed at a niche audience that loves epic fantastic adventure, futuristic mecha battles, and romantic underdog victories. If you fit that description, then you'll get plenty of enjoyment out of the Robotech novels.