  We review more than 10 years of continuous monitoring of accreting X-ray
pulsars with the all-sky Gamma-ray Burst Monitor (GBM) aboard the Fermi
Gamma-ray Space Telescope. Our work includes data from the start of GBM
operations in August 2008, through to November 2019. Pulsations from 39
accreting pulsars are observed over an energy range of $10-50\,$keV by GBM. The
GBM Accreting Pulsars Program (GAPP) performs data reduction and analysis for
each accreting pulsar and makes histories of the pulse frequency and pulsed
flux publicly available. We examine in detail the spin histories, outbursts and
torque behaviors of the persistent and transient X-ray pulsars observed by GBM.
The spin period evolution of each source is analyzed in the context of
disk-accretion and quasi-spherical settling accretion driven torque models.
Long-term pulse frequency histories are also analyzed over the GBM mission
lifetime and compared to those available from the previous BATSE all-sky
monitoring mission, revealing previously unnoticed episodes in some of the
analyzed sources (such as a torque reversal in 2S 1845-024). We obtain new, or
update known, orbital solutions for three sources. Our results demonstrate the
capabilities of GBM as an excellent instrument for monitoring accreting X-ray
pulsars and its important scientific contribution to this field.
