The scientific requirements and formats for clinical study authorizations (CSA) — IND, CTX, CTC, CTN, etc. — vary considerably from country to country. In some cases they are virtually nonexistent. A comparison is made of the situation in some of the most demanding countries — Australia, Sweden, United Kingdom, and the United States — to highlight differrences and similarities. Further, the levels of the CSAs required to proceed through Phase I–III are considered as steps which eventually culminate into marketing authorization applications (MAA). Such a stepwise development strategy is bound to result in more easily prepared MAAs which may be more quickly approved