The Starseed Signals, which I am still slowly reading, has quite a bit on "Paul Segall, a PhD candidate at UC-Berkeley, who has been involved in life-extension research for fifteen years," including a long passage in Chapter 11 which quotes him for pages and pages, based on what Wilson says was a three-hour interview. Of course, this befits the "life extension" part of the SMI2LE formula of Timothy Leary, e.g. space migration, intelligence increase and space migration.
This made me curious about what happened to Segall. Was he still alive and doing his research? Would he perhaps be available for an interview?
The scientist named "Paul Segall" who is easiest to find on a search engine is a Stanford professor of geophysics who is an expert on volcanoes, obviously not the same person. But eventually I found the sad news that the Paul Segall in the book died in 2003, age 60. See this article, I also found this obituary, and this press announcement. It's not clear whether he was cryonically preserved; I could not find an official obituary, does anyone have more information?
Incidentally, while it is easy to point out that SMI2LE has not advanced as quickly as Wilson predicted, work on all aspects of it continues. The "space migration" part is pretty obvious if you have heard of folks such as Elon Musk and Jeff Bezos; work on artificial intelligence is much in the news, and I run across interest in life extension at libertarian websites and blogs. For just a couple of examples, see this blog post at Marginal Revolution, and see also this one.
At the time of his death, Segall was chairman, co-founder and CEO of BioTime Inc. The name of the company was changed last year to Lineage Cell Therapeutics, a cell therapy company that is publicly traded.
I cannot find a photo of Paul Segall that isn't under strong copyright, so I have a screenshot of the website for the company he founded.