Introductory Remarks＆by Alan A．Boyden 1
1．Comparative Serology:Aims,Methods,and Results＆by Alan A．Boyden 3
2．Physical and Chemical Factors of Significance in Antigen-Antibody Reactions＆by David Pressman 25
3．Structural and Energetic Aspects of Antibody-Hapten Interactions 40
4．Immunochemical Studies with Some Native and Chemically Modified Proteins＆by Paul H．Maurer and J．Sri Ram 56
5．Characterization of precipitin Systems by Direct Photometry of Agar Columns＆by William G．Glenn 71
6．A Critique of Precipitin Methods as Applied to the Elucidation of Immunochemical Relationships Among Antigens＆by Elvin A．Kabat 92
7．Serological and Biochemical Comparison of Proteins－Summary of the Conference＆by Felix Haurowitz 113