It’s certainly worth reviewing the first few links below which summarise and present many aspects of the history and evolution of the RTL-SDR into a great desktop SDR device, for both education and development.
“About RTL-SDR”, from RTL-SDR.com.
Sylvain, “RTL-SDR: Specifications”, from OsmoCom SDR.
Karsruhe RTL-SDR Project, from Karlsruhe Institute for Technology.
H. Welte, “RTL-SDR – Presentation”, given at FreedomHEC 2012 Taipei.
rtlsdr.org, Some RTL-SDR Wiki pages.
A. Wolke, “Build, test, use the RF Noise Source on the Ham-It-Up RTL-SDR Upconverter”, YouTube.
MathWorks SDR Discovery pages.
NooElec, Software Defined Radio Hardware.