If your customers don't sleep, why should your reference service? Online library reference services available 24/7 are offered in a growing number of institutions. With many models to choose from and more details to be worked out, it is a critical time for librarians to assess their patrons' needs and market their services to address these needs. Collecting and documenting what thousands of virtual reference librarians have learned over the past few years, this comprehensive guide provides a needed overview to help new and aspiring virtual reference library departments - and their directors...