The advantage of this book is that you get all of the Central Asian languages - and Russian - in one compact book. The Tajik is the Samarkandi dialect, spoken by Tajiks in Uzbekistan, so there are some minor differences with the language as spoken by Tajiks in Tajikistan. Watch out also for several translation errors.
This phrasebook uses Latin script throughout and has no Cyrillic text. This has the disadvantage that you can't point to the phrase, you have to have a go at pronouncing it. Apart from this weakness, it is a reasonably good phrasebook for a beginner in the language. It includes a section on Tajik grammar.
Linguaphone offer several Russian courses, at beginner/intermediate levels. Most of the courses are based on Linguaphone's tried and tested book/audio (CD or cassette) format. At beginner level, there is also the option of a multimedia Russian course on CD-ROM.