  The goal to describe plutonium phases from ``first principles'' calculation
methods is complicated by the problem of 5f-electrons localization. While for
early actinides (Th, U,Np) standard DFT (Density Functional Theory) description
with itinerant 5f-electrons works well for late actinides (Am, Cm) DFT
calculations with completely localized (pseudocore) 5f-electrons give
satisfactory results. However plutonium presents a border case of partial
localization and both limits (itinerant and completely localized) are not
valid. We present a review of the methods used to solve this problem and
discuss what could be the reasons for their successes and failures.
