Living Starship: The genesplicing esseli and the residents of Kythera – the Empire’s masters of biotech – are the chief users of this sort of technology in the Imperial context, although they’re by no means the only ones in the Associated Worlds to go for this sort of thing.  Although, in deference to certain realities about the capabilities of carbon-based organics vis-à-vis metal and ceramic, the hulls (mostly, although some specially-engineered and composite-laced wood-analogues are an exception), engines, and other high-energy components tend to be not living in anything resembling the conventional sense; i.e., the ships are only semi-organic.  (See also, for example, the note under Flesh Versus Steel about the Gardeners of Rechesh; while they do manage to construct entirely biotech spacecraft, their hulls are vulnerable and engines slow compared to virtually anything else anyone’s ever put into space.)