Although there are quite literally hundreds of magazines in this category, and many of them have subtitles, all but a few fall into 2 main subcategories. Those subcategories are shown below - one is the "BEST OF GENESIS" series and the other is "GIRLS /GIRLS" (the first few issues of this particular title were actually part of the "Best of" series until being spun off as a separate title in 1984.
GENESIS began it's highly popular 'Friends & Lovers' Amateur Erotic Photo Contest feature in the issue of Sept, 1978. Just about a year later the very first Genesis special appeared, Not surprisingly it was a compilation of the women featured during the previous year and titled "Friends & Lovers Amateur Erotic Photo Album". It included the 12 months from 9/78 - 8/79. A year later (in late 1980) the 2nd volume of the series appeared bearing the same title and the #2 designation and indicating an annual publication frequency. It seems reasonable to assume sales of this issue were farily good since it was only 6 months later that the 3rd volume was published covering the period from 9/80 -2/81 and doubling the frequency of publication to semi-annually.
Sometime during 1981 it was determined that the "BEST OF GENESIS" would be the umbrella title under which all the specials would be published. Also adopted was a system of numbering the issues using a standard Volume, Number notation. This accounts for the appearance late in 1981 of the 4th issue in the series (covering the months 3/81 -8/81) being designated V.3, #5. The number 5 apparently is the total number of special issues to that point, over a period of 3 years.