Complex sentence: Henry Spencer Ashbee (21 April 1834--29 July 1900) was a book collector, writer, and bibliographer, notorious for his massive, clandestine three volume bibliography of erotic literature written under the pseudonym of Pisanus Fraxi.
Split into simpler sentences: Henry Spencer Ashbee (21 April 1834--29 July 1900) was a book collector, writer, and bibliographer. He is notable for his massive, clandestine three-volume bibliography of erotic literature written under the pseudonym of Pisanus Fraxi.