Letters of inquiry are being accepted on Proposal Central for the Simons Foundation Targeted Grants in Mathematics and Physical Sciences program. The deadline is August 31, 2017. This program is intended to support high-risk projects of exceptional promise and scientific importance on a case-by-case basis.There is no targeted or assumed funding duration or level for this program. While there are no fixed guidelines, projects at the single- or few-PI scale that might be funded by federal agencies would not normally be considered under the Targeted Grants in MPS program. The emphasis of the program is on theory, but projects with some experimental components may be considered.