All the commandments applicable in our time, including those contingent upon the Land of Israel, with invaluable commentary and explanation. Hebrew text with facing English translation.
This edition of the Chofetz Chaim's The Concise Book of Mitzvoth (ספר המצוות הקצר) is a handy pocket-sized resource detailing those of the 613 mitzvos which are applicable to the diaspora (an addendum to this edition also includes those mitzvos which are applicable only within Eretz Yisroel).
It's small size and brief entries make this a handy on-the-go study guide. Each entry provides a concise description of the mitzvah under discussion, sometimes including related rabbincal prohibitions, along with, where relevant, the original punishments laid out in Torah and rabbinical law (I suspect one would be hard-pressed to find another book of similar brevity that incorporates so many instances of the phrase "whiplashes of disobedience").
This book is a useful addition to any Jewish library.