The development of a new chemical entity for human use is a stepwise process based on an assessment of both animal and human data on efficacy and safety of the drug. Clinical pharmacologists always refer to animal data through an Investigator's Brochure (IB) when planning and performing a clinical trial(s). The IB should provide the investigator (s) with useful information to select doses, dosing intervals, and safety monitoring procedures and also to support the clinical management of subjects during the trial(s). Non-clinical animal studies contained in the IB, however, lack a relationship to the pharmacological and toxicological findings of the investigated product(s). Most of the non-clinical animal studies address the methodology and the results obtained, but are lacking in a discussion of the relevance of the findings. The IB shoud include not only a summary of the findings in each field of animal study but also relationships of the findings through some indicator (s) such as blood and tissue concentrations of the parent drug and/or metabolites. I do hope Pharmaceutical Companies will provide much useful information about their product (s) through the improvement of their system of research and development.