On the Fradkin-Vasiliev formalism in d=4

Here we provide a short review on the so-called Fradkin-Vasiliev formalism for the construction of higher spin cubic interactions. Initially it was formulated for the massless fields only, but later on it was extended to the arbitrary collections of massive and massless fields.
Comment: 16 pages. Expanded version of the talk given at "Fradkin Centennial Conference", September 2-6, 2024, Lebedev Institure, Moscow