Well, while I could probably write pages of material on this......I don't need to because the proponents and pioneers of this integrated approach to diving have been very prolific in sharing their philosophy online and many of those articles and gear configuration illustrations are still available online. So this will be a link-rich post.
Much of the innovation and experimentation in dive equipment configurations can be traced to the cave diving pioneers of the 1980s. Particularly, Sheck Exley, Bill Hogarth Main and Bill Gavin. This is where the "Hogarthian" system comes from. In short the Hogarthian system is about minimalism and functionality, "If you don't need it, don't bring it." For a more complete discussion of the Hogarthian system, please read this Jarrod Jablonsky article from several years ago.
From this foundation, the next generation of deep cave explorers, led by the guys at the WKPP, took this philosophy and refined it to what is today called "Doing It Right", or DIR for short. Frustrated by what they perceived to be a dangerous focus on "card collecting" in the dive training industry and a general lack of experience among "technical divers", they formed a new dive training organization, Global Underwater Explorers ("GUE"). From the mid-1990s to the early-2000s, George Irvine, Director of WKPP was prolific, vocal and confrontational in spreading the DIR philosophy online. If you want to get a feel for this, just do a quick search on "Irvine" in the techdiver listserv archives. This is where I was first exposed to DIR. Now through GUE, they have the ability to formally mold divers in their image. Please fully explore the GUE and WKPP sites for more information.