Аннотация:This article reviews observational data on cataclysmic variables (CVs) whose orbital periods fall within the so-called period gap between 2 and 3 hours. The orbital period distribution of cataclysmic variables and the filling of the period gap by various types of CVs are demonstrated. Roughly half the stars in the period gap are magnetic, of which the majority are polars, while the other half (except a few stars) are SU UMa-type stars characterized by superbursts and superhumps. It is also interesting to note that those intermediate polars whose periods fall within the gap are among the stars with constant superhumps. The height above the galactic plane is estimated for the nonmagnetic stars and it is shown that, contrary to predictions, the stars in the period gap do not belong (except for one) to the spherical component of the galaxy. Light curves, some characteristic times, burst amplitudes, etc. are given for a number of Su UMa-type stars observed by the authors. The evolution of superbursts from the stars NY Ser, V725 Aql, and Var73 Dra is described. Observational data are presented on the classical nova V Per, a star whose period lies right in the middle of the period gap but whose status (magnetic or nonmagnetic) has still unclear.