Sci-fi book about humanity barely winning a war with an alien race, after which the protagonist discovers some secrets about the conflict

Question

I am looking for a sci-fi book from the '80s or '90s. On the blue cover there was an astronaut, bearded and balding I think. The story was about humanity who fought a war with an alien race and won, barely. They won because they figured out teleportation, and a teacher who became a commander led the resistance to victory.

The protagonist of the book finds out some secrets of the conflict after the war. The alien ships are often described as having a round or circular shape. One story I remember of the conflict was that humanity rigged an explosion to trigger a sun to go supernova to take out the alien fleet but it didn't come to fruition because a woman took out the man who disabled the automatic trigger and wanted to trigger the explosion manually. Another story was the protagonist had an affair with a woman who had a crash on an ocean planet with her shuttle and drowned.

Humanity now lives on several planets. Not exactly sure how many. The book didn't seem to be part of a series, but rather a standalone novel. Any ideas?

Answer 1

A Talent for War by Jack McDevitt

The cover shows a bearded face under a helmet with a shiny surface (rather than balding). Published 1989.

The story is told from the point of view of Alex Benedict, researching the war decades later after his uncle dies mysteriously.

• Christopher Sim was the leader of the resistance at the start of the war against the Ashiyyur, before the human worlds united to battle them. In chapter IX (emphasis mine):

The early pages of Man and Olympian are filled with Xerxes' rage ("O Master, remember the Athenians"), Themosticles' statesmanship, and the valor of the troops who stood at Thermopylae. I was struck, not only by the clarity and force of the book, but also by its compassion. It was not what one would ordinarily expect from a military leader. But then, Sim had not begun as a military leader: he'd been a teacher when the trouble started.

The loss by drowning of Quinda in chapter XVII:

"Quinda," I shouted. "Hang on. Hang on to him. We're going to bring you both up." I was tying the line around the seat anchor.

She shook her head. I couldn't hear her, but she pointed at the line. It wouldn't be strong enough to support both. To emphasise the point, she pushed away and shouted something else. Over the roar of sea and wind I understood: "Come back for me."

...

When I got back out on the wing, she was gone. I stood there, trailing the cord, calling her name, not even certain where she'd been, until the Patrol vehicles circled in and took station overhead.

They searched until dawn. But there was never any hope.

One slight difference is that it is not teleport that was discovered but rather a much faster version of the jump drive than was in use by others.

Will add quotes shortly to support.

Answer 2

I do not remember the cover, but the plot you describe sounds identical to Rockets in Ursa Major by Fred & Geoffrey Hoyle. The spherical alien ships, the lithium bomb used on the sun to destroy the alien fleet. Followed up with novel Into Deepest Space.

The science in these books was so suspect that even a preteen (me) was able to see the through it.