"Koi no Kamisama" (God of Love) by Komi Naoshi. Before Komi-sensei made it big with "Nisekoi", he had one other series and 6 short stories. This book contains all of those short stories. It's sample of how the artist's career has developed.
Despite the book being titled "Koi no Kamisama", majority of the stories here do not fit in the romantic genre: "Island" is about a walled nation where the children dream of exploring the outside world. "Williams" is about a young boy who sought after the seemly fantastic adventures he had read. "Personant" about a future society where everyone wears masks. "Apple" is a science fiction regarding the ultimate lifeform that would protect the earth. The plot for these are all very well thought out with no loose ends, and each comes with a twist that ends the story on a positive note. They are all great to read, but you might wonder how this author ended up drawing something like "Nisekoi" later.
The answer lies in the two remaining two stories: the first one is "Koi no Kamisama", a romantic comedy about a boy's pursue for one particular girl's affection, which has been made very difficult because he is competing with a god who shares the same affection for this girl. Komi-sensei wrote in the afterwords about how this particular story was well received, but he didn't fully understand why this story was popular.
The last story is "Nisekoi", the prototype to the current "Nisekoi" series (currently at volume 18). A coworker described it as "the opposite of Romeo and Juliet", which is a fairly accurate description for the series, and even more accurate for the prototype. I am sure by the time Komi-sensei got this far, he has totally figured out exactly what the readers wanted, and continue to expand "Nisekoi" with all the extra colorful characters and back stories that made it popular.
The other series before Nisekoi was "Double Arts", it had an interesting setting and lots of fun characters, but it got cut off short after just 3 volumes, it's a real shame. "Island" was a bonus collected at the end of the first volume, and reading it was enough motivation for me to find all other stories drawn by Komi-sensei. All those short stories are collected in this one single volume, it's such a great deal! It was totally worth reading.
Note: "Island" is available in its entirety, here:
http://www.s-manga.net/book/978-4-08-880119-3.html
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