Alongside these are many of the subsequent editions, which show Darwin's careful revision and updating of his scientific work, and a large selection of books about Darwin's life and work.  Dr. Irvin expanded the collection from this core to acquire selected works of Darwin's predecessors (his grandfather Erasmus Darwin, Malthus, Lamarck, and Lyell) and by selected contemporaries and allies.   

Since its donation, the collection has been significantly expanded with the help of the endowment established by Dr. and Mrs. Irvin.  The few gaps among the Darwin firsts (notably the geology and barnacle books) have been filled, and systematic efforts have been made to add (1) the books mentioned as precursors by Darwin in his historical preface to the third edition of the Origin of Species; (2) the works of Alfred Russel Wallace; and (3) previously-lacking books by T.H. Huxley.  The collection holdings are searchable in the library's on-line catalogue.

The Irvin Collection was first exhibited at Thomas Cooper Library in 1992, with a printed catalogue prepared by the exhibit's curator Roger Mortimer.  This much-expanded web exhibit sets out both to chart Darwin's career and to illustrate his achievements and influence, setting Darwin's own books in the context of works by his scientific contemporaries.  The focus is as much historical and educational as it is strictly bibliographical.  It is based on the exhibition mounted for the lecture series Darwin Across the Disciplines in March 1999, updated to incorporate more recent acquisitions.

A Note on the Significance of Darwin, by Roger Mortimer
(from the 1992 exhibition catalogue)
Similarities between man and other vertebrates have been noted and discussed by Western thinkers since Classical times, and numerous theories, many of an evolutionary nature, have been formulated to account for those resemblances. It was not until the early nineteenth century, however, that knowledge of existing plant and animal morphology, coupled with the study of the record of past life preserved in the geological time scale, permitted the scientist to begin to draw precise parallels between present-day life-forms and to relate them to fossil antecedents.
       Assisted by this scientifically definable methodology, Charles Darwin was able to formulate a theory of evolution free of the theological or metaphysical implications inherent in earlier evolutionary theory. His theory of evolutionary selection holds, simply, that variation within species occurs randomly and that the survival or extinction of each organism is determined by that organism's ability to adapt to its environment. Though aspects of the mechanism of natural selection continue to be debated in the scientific community, Darwin's principal thesis remains central to modern scientific thought.