“…However it is unknown whether or not n-Engel groups, that is, those satisfying the law [x, n y] = 1 for some fixed n, must be locally nilpotent (although this seems unlikely). This has been established for n < 3 (see [6]), and, for general n, for the class of residually finite n-Engel groups [11]. (Note that there are relatively easy examples of non-nilpotent «-Engel groups; see, for example, [8, p. 132] In the present note we call attention to a simple general fact about Engel groups which has apparently hitherto gone unnoticed, and from it infer firstly the local nilpotence of Engel 'SB-groups' (these are defined below; they include soluble groups), and then a quite specific global description of the n-Engel groups in a large class "io of groups (including soluble and residually finite groups), yielding in particular their local nilpotence.…”