A charitable deduction, however, may not be allowed for the donation of a partial interest in the property. The IRS recommends that the value of books be determined by selecting comparable sales and adjusting the prices according to the differences between the comparable sales and the item being evaluated. The IRS recognizes, however, that this is difficult to do and, except for a collection of little value, should be done by a specialized appraiser. Merely because a book is old, and appears to be rare, it may not necessarily be valuable, because it could have little or no market value. In that context, the condition of the book could affect its value.
Collectors are interested in items that are in fine or at least good condition.
When a book lacks pages or is in weakened condition with a shaken binding or stained pages, its value can be lowered. Beyond these basics, one may be influenced by the historical and intellectual impact of the work, its fame, number of editions, place in the development of typography and the physical book's intrinsic value as a beautiful object, an example of the printer's or book binder's art. Manuscripts, autographs, diaries and similar items when handwritten or signed by famous people are considered valuable. The historical or legal importance of the occasion for these items can add significantly to their value as well. The IRS stresses that the weight given an appraisal will depend on its completeness and the qualifications of the appraiser.