This paper reviews recent determinations of the present-day mass function (PDMF) and initial mass functions (IMF) in various components of the Galaxy, including the disk, spheroid, young clusters, and globular clusters. The IMF is found to depend weakly on the environment and is well described by a power-law form for masses greater than 1 solar mass ($M_\odot$) and a lognormal form below, except possibly for early star formation conditions. The disk IMF for single objects has a characteristic mass around $m_c \sim 0.08 \, M_\odot$ and a variance in logarithmic mass $\sigma \sim 0.7$, while the IMF for multiple systems has $m_c \sim 0.2 \, M_\odot$ and $\sigma \sim 0.6$. The extension of the single IMF into the brown dwarf regime agrees well with current estimates of L- and T-dwarf densities, yielding a disk brown dwarf number density comparable to that of stars, $n_{BD} \sim n_* \sim 0.1 \, \text{pc}^{-3}$. The IMF of young clusters is consistent with the disk field IMF, confirming that young star clusters and disk field stars represent the same stellar population. Dynamical effects, leading to the depletion of the lowest-mass objects, become significant for ages greater than 130 million years (Myr). The spheroid IMF is less well constrained, with a large metallicity spread in the local subdwarf photometric sample remaining puzzling. Recent observations suggest a continuous kinematic shear between the thick-disk population and the genuine spheroid, allowing only an upper limit for the spheroid mass density. Within uncertainties, the spheroid IMF is similar to that of globular clusters, represented by a lognormal form with a characteristic mass slightly larger than for the disk, $m_c \sim 0.2$-$0.3 \, M_\odot$, excluding a significant population of brown dwarfs in globular clusters and the spheroid. The IMF of early star formation at large redshifts remains undetermined but is expected to extend below $\sim 1 \, M_\odot$. These results suggest a characteristic mass for star formation that decreases over time, from conditions at large redshifts to present-day conditions. The paper also discusses the implications of these IMFs for the Galactic mass budget and mass-to-light ratios, and examines the current understanding of star formation theory.This paper reviews recent determinations of the present-day mass function (PDMF) and initial mass functions (IMF) in various components of the Galaxy, including the disk, spheroid, young clusters, and globular clusters. The IMF is found to depend weakly on the environment and is well described by a power-law form for masses greater than 1 solar mass ($M_\odot$) and a lognormal form below, except possibly for early star formation conditions. The disk IMF for single objects has a characteristic mass around $m_c \sim 0.08 \, M_\odot$ and a variance in logarithmic mass $\sigma \sim 0.7$, while the IMF for multiple systems has $m_c \sim 0.2 \, M_\odot$ and $\sigma \sim 0.6$. The extension of the single IMF into the brown dwarf regime agrees well with current estimates of L- and T-dwarf densities, yielding a disk brown dwarf number density comparable to that of stars, $n_{BD} \sim n_* \sim 0.1 \, \text{pc}^{-3}$. The IMF of young clusters is consistent with the disk field IMF, confirming that young star clusters and disk field stars represent the same stellar population. Dynamical effects, leading to the depletion of the lowest-mass objects, become significant for ages greater than 130 million years (Myr). The spheroid IMF is less well constrained, with a large metallicity spread in the local subdwarf photometric sample remaining puzzling. Recent observations suggest a continuous kinematic shear between the thick-disk population and the genuine spheroid, allowing only an upper limit for the spheroid mass density. Within uncertainties, the spheroid IMF is similar to that of globular clusters, represented by a lognormal form with a characteristic mass slightly larger than for the disk, $m_c \sim 0.2$-$0.3 \, M_\odot$, excluding a significant population of brown dwarfs in globular clusters and the spheroid. The IMF of early star formation at large redshifts remains undetermined but is expected to extend below $\sim 1 \, M_\odot$. These results suggest a characteristic mass for star formation that decreases over time, from conditions at large redshifts to present-day conditions. The paper also discusses the implications of these IMFs for the Galactic mass budget and mass-to-light ratios, and examines the current understanding of star formation theory.