When the knowledge takes the shape of a document, it involves certain additional features not found in the Universe of Knowledge. These drive from the subtle and gross embodiments involves in a book and from readers service, in order to fulfill the laws of Library Science. Additional features are:
- a) Quasi class: The class which is specific in nature.
- b) Local variations: Based on local problems.
- c) Composite documents: Documents which have complex nature.
- d) Partial comprehension.
- e) From or medium of expression: Medium which is used for expression.
- f) Related documents: Documents which are based on likeness.
- g) Physique of the documents: Physical body of the document.
Ranganathan enunciated three parts of document classification:
i) Book number;
ii) Collection number;
These are also called Canons. These are the additional canons.
Special Features of Document (Book) Classification
- It is a structural organization of knowledge.
- It is well-constructed.
- It will serve with maximum efficiency of functional organization of knowledge.
- It consists of grouping and sub-grouping of subjects.
- Grouping is based on experience and further requirements.
- It is well-qualified to serve.
- It is established in the scientific and educational concerns.
- It leads to efficiency.
- It leads to adequacy.
- It leads to educational value.
- It is practical classification.
- It is a purposeful classification.
Limitations of Book Classification
- Its purpose to arrange books and other materials in helpful order. It depends on careful consideration of possible facet formula within each subject.
- No helpful order can satisfy fully.
- The passage of time leads radical changes of classification scheme. tremendous labour is required to meet the challenge of enormous increasing record.
- Even the best book classification is unable to bring together all the material on the shelves. Books can be scattered according to their nature.
- Inter-discipline researches have put a problem before the classifier to keep books of just similar thoughts together.
- Poor and faulty work of the classifier in difficult and unfamiliar fields.
- Inaccurate and makeshift decisions due to poorly constructed and outdated table of classification.
- Long and confusing notation for specific subjects.
- It is effective for one language only.