The structures and the vibrational dynamics of the complexes HHe + n are investigated experimentally (via mass spectrometry (MS)) and at high levels of electronic-structure theory. The MS measurements reveal interesting trends about the stability of the starting members of the HHe + n family. The computations establish that the basically linear, strongly bound, symmetric triatomic molecular ion He(H +)He, with an equilibrium H-He distance of 0.925 Å and about 2/3 but at least 1/2 of the positive charge on H, is the molecular core of all of the n ≥ 3 complexes. Definitive quantumchemical results are obtained for HHe + and HHe + 2 , including the proton affinity of He (computed to be 14, 876 ± 12 cm −1 via the focal-point analysis (FPA) scheme), the FPA isomerisation energy between the two linear isomers of HHe + 2 (3826 ± 20 cm −1), and the dissociation energy of the HHe + 2 → HHe + + He reaction, with an FPA estimate of 3931 ± 20 cm −1. The structural isomers of the He-solvated complexes are discussed up to n = 18. A useful notation, [k−l−m]-HHe + n , is introduced to characterise qualitatively the three possible belts around the He-H +-He core in HHe + n (n ≥ 3), where l denotes the number of He atoms in the central belt and k ≥ m denote the number of He atoms in the top and bottom belts. Capping He atoms attached to the belts can be indicated by sub-and superscripts. Several possible indicators of microscopic superfluidity are investigated: He evaporation energies, rotational constants, and vibrational fundamentals.