Having used this book and the cassettes off and on since 2005, I've had a lot of mixed feelings. At times I've absolutely hated the book, and at other times I've felt it was pretty valuable. In reality, the Farsi/Persian books available usually aren't the best. While one book excels in a certain way, it fails in another. As for "How to Speak, Read & Writer Persian," I feel it fails the beginning student to learn the basics while helping the intermediate student to excel in the colloquial language. It may seem strange since this book is meant to be a complete self-teaching method, but this has been my experience. Each lesson contains a dialogue, one or two vocabulary lists, a grammatical description of one or more topics, usually a reading practice, and several exercises. This sounds good, except the exercises are not varied nor large enough to solidify the chapter's contents in your head. Although the author does read the dialogues and much of the vocabulary in a slow, deliberate manner (which is great for the beginner), he doesn't have any Iranians acting out the dialogues with him. It would have been much more realistic and engaging if so, aiding the long-term investment of the student. The dialogues are fine for small talk, but beyond that they are not sufficient since they're mostly about inquiring the status of a person's health, asking if he/she is married, if the person likes Persian food, etc. Moreover, the book feels very artificial and segmented. As a beginning student it is not very beneficial to always need to fill in the gaps and tie everything together--that should be the author's job. However, if one is an intermediate student, s/he should be at the stage in which a nicely flowing method is not of the same necessity, and s/he is experienced enough in the language learning process to deal with these inadequacies.
I have thus rated Amuzegar's book 1 star for the beginner, but for a student who already has a solid working base in Farsi, I would rate this book a 3.5 out of 5. I recommend going to easypersian dot com as it's one of the best methods available, and all for free, to learn Persian. After doing maybe 50 lessons there, you'll appreciate certain qualities of "How to Speak...Persian" that you wouldn't have prior. As a beginning student I felt I got a lot out of "Teach Yourself Modern Persian" by John Mace, the 1960s edition--however, it is literary-based, and a lot of the vocabulary is archaic. The new edition by Farzad seems okay, but I haven't used it enough to recommend it. Book 1 and the CDs of "Contemporary Spoken Persian" is a good set for the beginner, learning the spoken word (and it's not written in the Persian alphabet), but it's horribly overpriced, too short, and is in great need of an extensive revision. Routledge's "Colloquial Persian" might be a good set to check out as well, but I do not own it. None of these resources are "grade-A, excellent" (except for the easypersian website--very commendable.), but with a lot of work you'll succeed. Easypersian dot com is always the beginner's best bet!
If a person must buy this book, then I recommend that s/he first familiarize her/himself with the Arabic script on pages 11 and 12; learn how to read and write them, individually and connected together. Then find an article in a book or magazine and write out the English words phonetically with the Perso-Arabic script. This really helps you to sound out the letters and know them intimately. Once ready, turn to page 23 and learn the "personal pronouns" such as "man = I", "mA = us", "shomA = you", etc. Turn to page 24 and learn the possessive adjectives and learn how they work, "-am = my", "-shAn = their", etc. Then turn to Lesson 3 (dars-e se) and on page 29 (safhe bist-o-noh) learn the verb "To be = Budan (boodan)" and pay close attention to the suffixes (the syllable at the end of the verb): "hast(am) = I am", "hast(i) = you are", nabud (no suffix) = he/she wasn't", "bud(and) = they were", etc. These suffixes will tell you whether the verb is referring to 1st person, 2nd person, and third person (singular and plural). Do any of the chapter exercises and learn the vocabulary and greetings to help you along. Then just skip to the chapters 8, 9, 10, 11, and 12. Chapters 8, 9, and 10 discuss present, past, and future verb tenses; 11 compound verbs, the use of the ezafe "ye," and interrogatives; and 12 the use definite suffix rA, colloquial contraction/elision, and prepositions. Once comfortable, skip back and all the rest will make more sense. Otherwise, you'll just cram word lists and dialogues in your head and still not know how to speak to Persians (plus, you're likely to forget the lists, etc anyhow!). I don't know if the author intended an "assimilation" into Farsi using the first chapters' dialogues, but it clearly didn't work for me.
The most useful feature of the book is the colloquial (spoken) Farsi learned through it, although at times it's not colloquial enough and its explanations are incomplete. On the other hand, as a beginning student I continually questioned the relevance of a "colloquial" and "written" Farsi. Little did I realize that Farsi is not spoken as it is written; thus the student will need to learn both to get a complete education in Farsi. For example,the long vowel-A (Alef) is often colloquially pronounced as "oo" (as in "soup") and also the long-vowel "o" (as in the first 'o' in "motor"). "IrAni" becomes "Irooni" and the same for khAne, which is "khoone". The Farsi word for "mother is "mAdar" and becomes "modar". Similar changes in vowels are made throughout the language in verbs, nouns, adjectives, etc. The book doesn't explain this until chapter 12. Also, maybe more importantly, verbs are almost always contracted to a simpler form in the present tenses. Although this is touched upon at times in chapters prior to 12, the author would have been wiser to add the colloquial version of each verb in the word lists in chapter 8 and thereafter, not waiting until 12 for discussion.
I'm glad I have the book and cassettes now that I'm passed the beginner's level, but I urge the authors to do some major revision.