2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/15196We present results of a weak gravitational lensing survey of six X-ray selected high-redshift clusters of galaxies. We find that the masses of the clusters derived from weak lensing are comparable to those derived from the X-ray observations. We show that many of the clusters have significant substructure not observed in the X-ray observations and that for the more massive clusters a singular isothermal sphere does not provide a good fit to the radial mass profile.5 pages, 1 figure, to be published in ASP Conference Series: Proceedings of Clustering at High Redshift, Les Rencontres Internationales de l'IGRAPAstrophysicstext