Manga, Artbooks and Other Literary items
the first manga series'Matantei Loki': there are two sets, one is released from GC, and the other is from Blade Comics. GC is smaller, and has a picture of how Kinoshita-sensei used to draw Loki. Blade manga is bigger, white, and has more features, such as author notes and extra parody pages included.
the second series 'Matantei Loki Ragnarok': currently only released by Blade Comics, they are black and so far only two volumes are available, though the 3rd volume is due out September 10. They are meant to be read AFTER the first series, since many of the characters are portrayed differently then in the series, and new characters(like Spika) are added. If you want to see what the manga looks like...(near the bottom of the page - thanks Maiki and Aila-chan! ^-^)
Matantei Loki "Much Ado about Nothing" (2980en) Also a great hard-cover book that features many color pictures from the manga and a couple from the series.
Matantei Loki Starter Book (780en) - Great book, has info on the main characters, voice actors, and pictures from the first two episodes.
"Comedy of Errors" - (2980en)the second art book from Kinoshita-sensei for Loki. More pics from the later manga, special pics from Loki things recently released and other little tidbits.
'Matantei Loki Ragnarok Perfect Guide Book' - (780en)appears to be like the Starter book above, but it is not available until Sept. 26.