Primer-directed sequencing, of double-stranded large recombinant DNA molecules, has not been accepted because of the delay and expenses involved in the synthesis of oligodeoxyribonucleotide primers. A potential solution to this problem was proposed by Studier [Proc. Natl. Acad. Sci. USA 86 (1989) 6917-6921] for using a library of short oligomer primers. Szybalski [Gene 90 (1990) 177-178] has made a complementary proposal using ligated hexamers to reduce the number of oligomers needed. We have used a set of rules for a computer-aided selection of a library consisting of 3342 specific nonamers. The effectiveness of this library of nonamers to sequence specific genes was studied using human sequences available in GenBank.