Gay fruit fly sex, of course. Enjoyable, well written, thought provoking with many details that I will probably forget.
This history of behavioral genetics is primarily presented as professional biography Seymour Benzer, a scientist who rejected the more lucrative field of solid state electronics to study the behavior of fruit flies. Benzer comes off as a part quirky professor, part inventive genius, and truly driven by the love (?, is that right) of his chosen field. The title comes from reducing behavioral genetics into three essential components - time, love and memory.
Time - we learn how the notion of clocks are built into our DNA
Love - more like mating patterns, but ok.
Memory - not just memory, but the ability to learn and change behavior because of it
Behavior is complex and understanding it is difficult. There is quite a bit written about the experimental approaches used and how behavior was broken down. Aside from the science, you learn some charming quirks that brings back memories of reading The Double Helix in high school (man those guys played a lot of tennis!). There are many featured players, including Watson and Crick of DNA structure fame.
Most important, it dances around the question of nature versus nurture. No conclusions are given, and as this was written 15 years ago, if any were they would probably be OBE by now.