Crashlander is a fixup by Larry Niven published in 1994. It brings together the short stories featuring the We Made It space pilot Beowulf Shaeffer — Neutron Star (Hugo Award winner, 1967), At The Core (1966), Flatlander (1967), Grendel (1968), The Borderland of Sol (1975) and Procrustes (1993) — and lightly links and extends them with Ghost.
Most of the stories were previously included in the 1968 collection Neutron Star.
For instance, two stories in the Crashlander short-story anthology consider separately the implications of a superfast hyperdrive ("At The Core") and medical nanotechnology ("Procrustes").
This is a reference to a third short story ("Flatlander") in the Crashlander anthology that describes the discovery of the antimatter planet Cannonball Express.
Another, more obscure reference to a Beowulf Shaeffer story, The Borderland of Sol, regards creatures that eat spaceships living in Hyperspace around gravity wells, thus explaining why ships cannot safely engage their hyperdrive close to a large mass (which was previously described as a singularity before this revelation).