Apparent density maps are derived from observed residual Bouguer maps under the assumptions that the sources are restricted to a depth interval and that the density distribution is not a function of the vertical coordinate. If the depth interval containing the sources is known, the computed apparent density maps are very close to the true density distributions. Even when the depth interval of the sources is not known, but the sources have constant density, their horizontal extent may be delineated by the half-maximum contours of the apparent densities. We developed an interpretation method using a family of curves based on source density, depth to top of sources, and source thickness.The main advantage in the use of these families of curves is the broad range of possible interpretations involving the above-mentioned parameters. Rough semiquantitative interpretations are possible in the absence of any further a priori information; more refined semiquantitative interpretations require additional quantitative knowledge of one parameter and just a lower or upper bound for another parameter. Finally, quantitative interpretations are possible only with additional quantitative knowledge of two of the three parameters involved.