The first two stories of NISIOISIN's Bakemonogatari series make up this collection and they're the perfect introduction to the writer and this world. Part comedy, part supernatural mystery and all about the eccentric characters of this world, both "Hitagi Crab" and "Mayoi Snail" are the perfect introduction to the character of Araragi Koyomi and his view of people and the world around him while also foreshadowing the mysteries of Hanekawa Tsubasa, which comes to a head in the third volume. Both Senjogahara Hitagi and Hachikuji Mayoi are very different but fascinating central characters in their respective stories and you'll be hard pressed not to fall in love with them in the end. There's no better place to start with the Monogatari franchise or NISIOISIN.