I. INTRODUCTION 2 The localized 4f -electron magnetism of lanthanide ions is by rule characterized by stable magnetic moments, which reflect the population of energy levels of the ground-state multi- plet determined by total angular momentum J and split by crystal field (CF) interaction. Paramagnetic susceptibility ( χ ) well above the magnetic-ordering temperature obeys the Curie Weiss law. This behavior may be modified at lower temperatures in the case of a considerable CF interaction. Sm represents an exception to this rule: Sm magnetism is not governed only by the ground state multiplet J = 5/2, since the first (and second) excited multiplet J = 7/2 ( J = 9/2) has only an energy of 0.1293 eV (0.2779 eV) $^{1}$. Therefore the temperature dependence of paramagnetic susceptibility at temperatures up to about 400 K is influenced by populating the CF split levels of the first and second excited multiplets via the temperature-independent Van Vleck terms 2 and does not obey the Curie-Weiss law. A typical 1/ χ vs. T plot for a Sm compound is strongly nonlinear and usually exhibits a maximum around 400 K, which is very sensitive to CF and exchange interaction $^{3}$. Since the samarium magnetic moment at low temperatures is small ( gJ = 0.71 µ$_{B}$ for the Sm 3+ free ion) exchange interactions can be very peculiar and several magnetic phases may appear in the same material at different temperature and magnetic-field intervals, respectively. In the present paper we demonstrate some specific features of Sm magnetism from the results of our recent study of a high-quality single crystal of the compound SmPd$_{2}$Al$_{3}$. We focused our attention on measurements of magnetization ( M ), AC susceptibility ( χ$_{AC}$ ), specific heat ( C$_{p}$ ) and electrical resistivity ( ρ ) as functions of temperature ( T ) and the external magnetic field ( B ). The anisotropy of magnetic properties has been determined from measurements in magnetic fields applied along the principal crystallographic directions [100] and [001]. Along with our experimental work, we performed various theoretical calculations of the electronic structure and CF parameters and compared calculated results with experimental findings. SmPd$_{2}$Al$_{3}$, as well as its RE Pd$_{2}$Al$_{3}$ ( RE = La, Ce, Nd, Gd) counterparts, adopt the same hexagonal PrNi$_{2}$Al$_{3}$-type crystal structure $^{4}$. It is worth noting that the U isostructural ana- log, UPd$_{2}$Al$_{3}$, is a well-known heavy-fermion antiferromagnetic superconductor ( γ = 150 mJ K $^{$_{−}$2}$mole$^{$_{−}$1}$, T$_{C}$ = 2 K, T$_{N}$ = 14 K) $^{5}$. The nonmagnetic analogue LaPd$_{2}$ Al$_{3}$ becomes superconducting at 0.8 K $^{6}$. The susceptibility of the Ce-, Pr-, Nd- compounds obeys the Curie-Weiss law at temperatures above 100 K.