Raych Seldon is a fictional character in Isaac Asimov's Foundation Series. He is the adopted son of Hari Seldon and Dors Venabili, the primary characters in the first two books of the series. He lived in the slums of Billibotton, part of Dahl, on the world of Trantor.

He married Manella Dubanqua, an undercover police officer who helped prevent an assassination attempt on Hari Seldon. They had two daughters, Wanda and Bellis.

When Raych was twelve, Hari Seldon and Dors Venabili fleeing from Demerzel, ended up in the lower-class sector of Dahl. On the quest for psychohistory, Hari Seldon needed information about the rumoured single planet home of humanity, Earth. He learned that Mother Rita, a citizen of Billibotton, had information about Earth. Needing to find the way to Mother Rita, Seldon grabbed a hold of Raych, and after some negotiating, convinced Raych to show him the way to Mother Rita. Along the way, Raych showed them the basics of their society plus a few hiding places in the sewers. Raych was a trustworthy and helpful guide through Billibotton for Seldon and Dors. As things got rough for Hari and Dors in Billibotton and Dahl, the two were taken to the Wye sectore of Trantor, along with Raych. They were welcomed into Wye, and met Rashelle, the heir of the throne of Wye. Like the rulers before, Rashelle wanted Hari Seldon, and psychohistory. Like before, Hari said no to the offer. Therefore, the upstart mayor-to-be of Wye, Rashelle, sent soldiers to capture Seldon and Venabili, Raych tried to defend them and received an intensely painful shock from a neuronic whip to his shoulder. In gratitude, Seldon and Venabili adopted Raych.

Eight years later, when Seldon was 40 and Raych was 20, a dangerously popular public speaker named Jo-Jo Joranum threatened to overthrow the Empire. Seldon recognized that Joranum had artificial hair, having been in Mycogen, and realized Joranum was an outcast, deciding to use that fact later. He also ordered Raych to pretend to become a follower of Joranum and then betray him. Raych's plan was to tell Joranum that First Minister Eto Demerzel, otherwise known as Daneel Olivaw, was a robot. Joranum believed this, because a) Demerzel really was a robot and could not give any definite signs to the contrary, and b) Raych seemed to emit a kind of trustworthy aura. (This is believed to be a rudimentary form of the mentalic manipulation later shown in his daughter Wanda.) Joranum made Demerzel's roboticity a major part of his campaign, and though at first the idea was considered ridiculous, the public started to wonder, and demand for Demerzel to prove humanity grew. Finally, at one of Demerzel's speeches, someone asked "Are you a robot?" Demerzel laughed. He had carefully practiced it with the Seldons and Dors (who had married Hari by that time). No one believed that a robot could laugh, however, and Joranum was brought down with that failure and with Demerzel contacting Sunmaster Fourteen, leader of Mycogen, and "discovering" that Joranum was a sacrilegeous traitor to their culture. The Emperor Cleon, under Seldon's advice, exiled Joranum to where he claimed to come from, the backwater planet of Nishaya. Demerzel left his post as First Minister, and Seldon replaced him.

Ten years later, Joranum's right-hand-man, Namarti, had strung the old conspiracy back together with the new head of Wye, Gleb Andorin, and was trying once again to replace Cleon. Seldon again sent Raych out, in disguise this time, to pretend to become a Joranumite named Planchet. While working on his mission, Raych met a recruiter named Manella Dubanqua, who he fell in love with. Manella introduced him to Gleb Andorin, who accepted Raych (under the name of Planchet). Andorin brought Raych to Namarti. However, Namarti recognized Raych, and determined that he would be useful in the plot against Seldon.

The Chief Gardener would soon retire, and with it the current staff. New gardeners would be brought in, without many questions asked. Namarti sent in several Joranumites, including Raych. In a few weeks, Seldon, along with the new Chief Gardener Mandell Gruber, would walk out into the field and give a welcoming speech to the new recruits. One of them would then pull out a blaster and kill Hari Seldon.

At lunch right before the speech, Andorin ordered Raych to do the job. Raych, of course, said "No. I told you I'd do anything for the Joranumites, but not killing." Andorin, however, had drugged Raych's food rather heavily with desperance, which caused the recipient to feel despair and lack the ability to disobey an order. Andorin quickly subdued Raych and then it was off to the ceremony.

The plan almost worked. However, another of the gardeners, Manella Dubanqua, an undercover law-enforcement officer, shot Andorin before he could order Raych to kill his father. After everyone had fled the scene, however, there was one person unaccounted for. Mandell Gruber picked up the dead Andorin's blaster and killed Cleon I. Gruber didn't want to become Chief Gardener, because he liked the outdoors and Chief Gardener was an organizing job, and, lacking a sense of proportion, he decided to kill the Emperor to prevent it. Apparently he didn't realize he would be immediately executed.

After recovering from the desperance, Raych married Manella. They later had two children, Wanda and Bellis. When Seldon was 70, Raych served as his bodyguard. Six years later, Hari Seldon, now 76, was gradually losing fundings and opportunity for his Seldon Project at Streeling University. Raych decided to move to another non-waning university, Santanni University. However, Santanni is 9,000 parsecs away from Trantor, and Hari was stubborn and not willing to move to another university. Some years later Santanni rebelled against the empire, and a riot formed. Raych was killed by bombardment from rebels, not willing to miss out on a fight. Bellis and Manella, who were on a ship to Terminus, mysteriously disappeared and were never heard from again. (Rumor has it that Bellis is related to the Gaian character Bliss, short for Blissenobiarella.)