The Proposal Database System (PDB) is the web-based interface for completing and submitting IODP proposals. PDB offers specific guidance and many proposal components are now created interactively; proponents are advised to begin working with PDB as soon as a proposal is planned. Complete proposal preparation guidance, format requirements, and review policies are explained in the IODP Proposal Submission Guidelines. A Call for Scientific Ocean Drilling Proposals is usually published at least two months in advance of the deadline with specifics about what types proposals are being sought. Proponents are strongly encouraged to contact the Science Operators to discuss platform-specific operational and fiscal constraints before developing proposals. The IODP Proposal Manager has sole authority to accept proposals or grant exceptions to deadlines and policies. Next Proposal Submission Deadline: April 3, 2017.