1. A computer-implemented method for realizing a virtual bookshelf, comprising: initiating a search query to locate one or more desired books in either physical or soft copy digital form; producing search metadata corresponding to the one or more desired books; filtering metadata corresponding to books contained within the virtual bookshelf with the search metadata to determine whether the one or more desired books is present in the virtual bookshelf, wherein the virtual bookshelf comprises information representing books, in either physical or soft copy digital form, acquired by and particular to a user; and outputting results of the filtering indicative of whether the one or more desired books is present on the virtual bookshelf.
1. A computer-implemented method for realizing a virtual bookshelf, comprising: initiating a search query to locate one or more desired books in either physical or soft copy digital form; producing search metadata corresponding to the one or more desired books; filtering metadata corresponding to books contained within the virtual bookshelf with the search metadata to determine whether the one or more desired books is present in the virtual bookshelf, wherein the virtual bookshelf comprises information representing books, in either physical or soft copy digital form, acquired by and particular to a user; and outputting results of the filtering indicative of whether the one or more desired books is present on the virtual bookshelf. 8. The computer-implemented method of claim 1 , further comprising: allowing the user to expand the search query to a specified on-line search service.