The Large External object-oriented Network Database (LEND) system has been developed to provide efficient access to large collections of primitive or multimedia objects, semantic networks, thesauri, hypertexts, and information retrieval collections. An overview of LEND is given, emphasizing aspects that yield efficient operation. In particular, a new algorithm is described for quickly finding minimal perfect hash functions whose specification space is very close to the theoretical lower bound, i.e., around 2 bits per key. The various stages of processing are detailed, along with analytical and empirical results, including timing for a set of over 3.8 million keys that was processed on a NeXTstation in about 6 hours.