We summarize mineralogical and compositional results from lab and in-situ spacecraft investigations of samples of comets 81P/Wild 2 and 67P/Churyumov-Gerasimenko which provide constraints to early solar system evolution. Wild 2 cometary solids were mineralogically similar to anhydrous chondritic Interplanetary Dust Particles with the exception that GEMS have not between reliably reported in the former. Important similarities include the very wide range of olivine and pyroxene bulk compositions (including minor elements), which probably reflects a wide range of sampled grain formation environments. The abundance of presolar materials in the Wild 2 samples is also approximately equal to that in anhydrous chondritic Interplanetary Dust Particles rather than being dramatically higher. High-temperature aggregates including chondrules (mainly type II), CAI and AOAs are also present in Wild 2, but probably at less than 10% overall total abundance. There was a pre-mission expectation that comet solids would be dominated by either non-crystalline materials, nanoscale crystalline materials, or presolar grains. None of these expectations proved to be correct. Organic matter was only well preserved in a few examined samples. These exhibit complex organic bonds, including mainly alkenes, aromatic C = C and carboxyl C = O, in a variety of textures including nanoglobules. The organic matter in Wild 2 samples show spectral similarities with that of insoluble organic matter (IOM) from carbonaceous chondrites. The chronology of the collected solids has not been well established, but there is no evidence for captured live 26Al, which could indicate accretion after this nuclide had effectively completely decayed. The implications of these major results are that Wild 2 sampled widely across the entire solar nebula, much wider than any other known astromaterials, potentially at a relatively late time compared to the oldest available astromaterials. A final caution is that the captured Wild 2 materials described here possibly derived from a small number of interior regions of a single Jupiter Family comet. There is also limited mineralogical information from comet 67P provided by the Rosetta Mission. The investigated 67P dust particles also contained about 45 weight% of solid organic matter, and is similar to the IOM extracted from carbonaceous chondrites. The H/C ratio of 67P IOM is about twice that of most carbonaceous chondrite IOMs and about 5 times that measured in asteroid Ryugu whole-rock samples, but lower than the H/C ratio of volatile species measured in the 67P coma. This high H/C ratio in the coma species is in turn compatible with that of the soluble organic matter in investigated carbonaceous chondrites such as Murchison. The average N/C ratio of 67P dust particles is about one order of magnitude lower than the solar photosphere value, but it is compatible with that of primitive carbonaceous chondrite meteorites and of Ryugu IOM.