Finding books

Books in the Central Library are now in one  numerical sequence across the floors, and items are now arranged as follows:


Level 2        0 – 532


Level 4        533 – 599


Level 5        600 – 999


Please note: The Library collections in both the Central and Silwood libraries are in the process of transferring from the UDC classification scheme to the Dewey Decimal System. This will obviously take some time to complete, but in the long-term will provide users with an easier system to locate items on the shelves. However, in the meantime it does mean that some items may appear in two places so it is important that you check the library catalogue to find the location of the items you are looking for.


Items that are already under their new Dewey number will have bright yellow spine labels, whereas UDC have white spine labels.


Dewey General Classification Numbers for the Life Sciences

570          Biological and Life Sciences
571          Physiology
572          Biochemistry
576          Genetics and Evolution
577          Ecology
578          Virology
579          Microbiology
580          Plants
582          Trees
590          Zoology
599          Mammals
612          Human Biology
616          Immunology
630          Agriculture and related technologies
634          Forestry

Biochemists may also require:

540          Chemistry
544          Physical Chemistry
546          Inorganic Chemistry
547          Organic Chemistry

As most of the collections are still functioning under UDC the information below will still be of use.


UCD General Classification Numbers for the Life Sciences


57            Biological Sciences in General

572.1/4   Human Development/General Origin of the Human Species

573          Biology

574          General Ecology and Biodiversity

575          Principles of Genetics

576          Cellular and Subcellular Biology

577          Material Bases for Life. Biochemistry. Molecular Biology. Biophysics.

578          Virology

579          Microbiology

630          Woodland Plants and Insects

631          Agriculture

632          Plant Diseases

633          Crop Plants

634          Trees and Woodlands

635          Cultivated Plants

636          Animal Agriculture

639          Fish Production


Biochemists may also require:


54            Chemistry

542          Practical Laboratory Chemistry: Preparative and Experimental

543          Analytical Chemistry

544          Physical Chemistry

546          Inorganic Chemistry

547          Organic Chemistry


Imperial College London Libraries (except the medical libraries) use the Universal Decimal Classification (UDC) scheme to classify items and file them upon the shelves. This page aims to provide a brief introduction to the scheme, explaining how to read the numbers and, therefore, find items more easily on the shelves.


When you have found an item on the library catalogue, you will see which library the item is at, how many copies are available, which location it is at (e.g. level 4), and there will be a number. This number is the number which the item is filed under on the shelves. UDC allows items to be grouped very accurately by subject, but this means that sometimes the numbers can be very long and a little confusing!


The Numbers


The numbers work like the digits after a decimal point, so 589.7 is filed before 59, which is before 6.


The Punctuation Marks


The various puncutation marks used in UDC mean various things, e.g. the colon : means that one subject is being applied to another, whilst the forward slash / means the item deals with two subjects. Understanding all the meanings of the punctuation is not necessary for locating an item on the shelf, however, remembering that these puctuation marks always follow the same order does help. By knowing that the comes before the . helps to stop you looking for an item two or three stacks of shelves away from where you need to be!


The order that the punctuation follows is:


/     e.g. 621/621.3

         e.g. 621

       e.g. 621:681.3

( )     e.g. 621(3)

.00    e.g. 621.003

–       e.g. 621-52

.        e.g. 621.1



Finding Theses

There are various routes you can take to finding theses.

Imperial College Theses:

Spiral, the College’s digital repository, has been created to provide a central point of collection of the College’s research publications; this includes theses. The full text of many theses can be viewed here.

Information about accessing theses which are only available in print can be found here.

Theses from other universities:

There are two excellent sources of theses information available:

EThOS the Electronic Theses Online Service managed by the British Library which allows you to search across 250,000+ theses for free and to order the full text quickly and easily.

Index to Theses is subscribed to by Imperial College Library and lists theses with abstracts accepted for higher degrees by universities in Great Britain and Ireland since 1716. Some access to full-text is available. (Please seach the Library catalogue for ‘Index to Theses’, access is by IP address, so if off-campus please use the VPN.)


  1. If you have class (94)338.48 Ind
    Would it be filed before (094.4)(036) Ind?

    Re: nothing before something rule.

    • Hi Una, I’ve asked our cataloguing team and they say that (094.4)(036) Ind would be filed before (94)338.48 Ind.
      Thanks, Elizabeth

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