Most books are heavy on grammar, which I believe is not the way to learn a language. Worst of all, most language books are dry, boring, and no fun at all. There are exceptions.
Breaking out of Beginner's Spanish by Keenan. This book is a gem. Anyone who is learning Spanish should get it. At last someone who tells us how real Spanish is used. Best of all Keenan has a great sense of humor.
When you are just getting started, I find it helpful to be familiar with the story, i.e. read the English version first, then jump into the Spanish and crack each sentence like a nut.
"Charlotte's Web" -- I found this in translation, and since the English text is readily available online and elsewhere, I have found it ideal. On top of that, the story is fun and is a chance to revisit something I enjoyed when I was much younger.
"La Alquimista" by Paulo Coelho -- This is recommended as a first book for a Spanish learner. I am going to need to learn more basic Spanish before I can tackle it. A disadvantage for me is that no English translation is in my hands. One is available, but you will either need to buy it or find a library copy. This could be viewed as a good thing if you want a challenge. My local library has 21 copies and it seems quite popular.
"Easy Spanish step by step" by Barbara Bregstein. Barbara is now my hero. I have had this book less than an hour, and I am already enjoying it and immediately learning things. This book is a 5 star winner and gets my highest recommendation
(I have said many times that tackling grammar as a beginner is totally the wrong approach, but this book really works well.)
"English Grammar for students of Spanish" I found a cheap online copy and will let you know when it arrives. This is part of a series "English Grammmar for students of xyz". I don't know if that is bad or good.
"Exacto" by Ortega et. al. This book is a well organized reference. It begins with a glossary, which is somewhat odd, but helpful. I would rather see a first couple of chapters that simply introduce grammar concepts in a systematic way. The index let me down in a quick "litmus test", when I tried to look up "lo".
"Fuentes" by Rusch et. al. A perfect example of the sort of book you should avoid. The first chapter starts off making you wonder where the book is that you should have had before this one. It might work if used in conjunction with a good teacher, but I suspect that a good teacher would select a different book. Fortunately I got a cheap used copy and can throw it away. I spent less than $5 on the copy I have and still regret the wasted money. I lose sleep at night thinking of bad things to say about this book. Three authors! Why didn't one of them step forward and do something about this mess.
Tom's Spanish pages / tom@mmto.org