  Information on cosmic-ray (CR) composition comes from direct CR measurements
while their distribution in the Galaxy is evaluated from observations of their
associated diffuse emission in the range from radio to gamma rays. Even though
the main interaction processes are identified, more and more precise
observations provide an opportunity to study more subtle effects and pose a
challenge to the propagation models. GALPROP is a sophisticated CR propagation
code that is being developed for about 20 years. It provides a unified
framework for interpretations of data from many different types of experiments.
It is used for a description of direct CR measurements and associated
interstellar emissions (radio to gamma rays), thereby providing important
information about CR injection and propagation in the interstellar medium. By
accounting for all relevant observables at a time, the GALPROP code brings
together theoretical predictions, interpretation of the most recent
observations, and helps to reveal the signatures of new phenomena. In this
paper we review latest applications of GALPROP and address ongoing and near
future improvements. We are discussing effects of different propagation models,
and of the transition from cylindrically symmetrical models to a proper 3D
description of the components of the interstellar medium and the source
distribution.
