The Game of Rat and Dragon is an early story in Smith's Instrumentality of Mankind series. The planoform ships that ply the stars are menaced by malevolent interstellar entities, and protected by pinlighters - parasite craft released from the host vessel carrying light bombs that can dispel the attackers. The pilots of the craft are sentient cats in telepathic communication with human controllers aboard the ship they are protecting. The cats perceive the attackers as rats, hence the title.
The cats are examples of Underpeople - animals genetically engineered to provide sentience - and used for various tasks deemed to risky for true humans. The fate of the Underpeople is an underlying thread in the Instrumentality series, with slowly growing attempts to see the Underpeople granted full rights as sentient beings.
All of Smith's work is simply wonderful.
Triplanetary is the first book of Smith's classic Lensman series. The others are First Lensman, Galactic Patrol, Gray Lensman, Second Stage Lensman, and Children of the Lens.
It details the conflict spanning eons between the Arisians and the rapacious Eddorians, invaders from another continuum, with humanity as Arisia's ultimate weapon.
It's classic space opera, and every time you think Smith has gone as far as he can, rest assured he has a topper up his sleeve, and a topper for the topper behind it,
This is based on the serial that appeared in Amazing Stories. The book publication differs. Alas, not all of the Lensman books have entered the public domain. (Magazine stories back then had a different copyright than the books, and often lapsed into the PD when the books didn't.)
This is a novelette set in Piper's "Federation" universe, which was also the setting for his classic "Little Fuzzy". It was expanded to novel length and published as "The Cosmic Computer" and "Junkyard Planet".
Conn Maxwell is the son of Rod Maxwell, a prominent planter on the planet Poictesme. Poictesme is economically depressed, and Conn has been sent to school on distant Terra.
Decades before the story takes place, the Federation had fought a war with the secessionist System States Alliance, and Poictesme had been a major advance base. An assortment of folks on Poictesme prospect for abandoned Federation supply dumps to salvage and resell the equipment. There have been rumors for many years that the Federation built and installed a super computer somewhere on Poictesme that was used to help manage the war, and many dream that if they find it, it can provide the answers to lift Poictesme out of economic stagnation and decline and make it a prosperous place again. Part of the reason Conn was sent to school on Terra was to gather information to aid that search.
Conn has returned home, and the search for the super computer is on, but what will the results be if it is found? The answers it can provide may not be those the searchers hope to hear.
It's one of a series Reynolds did under the general title "Frigid Fracas". The US and the Soviet bloc have recognized common interests and become much like each other. A world peace has been imposed, and weapons development strictly limited.
The US has what is called "People's Capitalism", with everyone issued Basic shares at birth and able to earn Variable shares in various manners. The social structure has stratified into Lowers, Middles, and Uppers based on shares held.
The protagonist is a Major in Category Military, hiring out to fight in various clashes. Corporations which cannot resolve differences by other means hire mercenary troops to fight for them. Combat is restricted to use of weapons designed before 1900, and the clashes are televised for the entertainment of the masses.