Baha'is not not always see things the same way. I do not consider everything that Baha'u'llah wrote as one book, but rather as many Tablets.
Number of tablets revealed by Bahá'u'lláh
by Robert Stockman and Juan Cole
1999
From Resource Guide, "scripture":
The writings, or tablets, of the Báb, Bahá'u'lláh, 'Abdu'l-Bahá, and Shoghi Effendi are stored at various places at the Bahá'í World Center in Haifa, Israel. Soon they will be moved to a building named "The Center for the Study of the Sacred Texts," which is under construction as of this writing. Microfiche copies of the tablets are also preserved for safekeeping at a variety of places around the world. Many texts were lost, stolen, or destroyed, and many others are still held in private hands. The estimated figures for the total number of individual tablets are as follows: Bahá'u'lláh, 7,160 tablets archived, 15,000 total estimated to have been written; 'Abdu'l-Bahá, 15,549 tablets archived, 30,800 total estimated to have been written; Shoghi Effendi, 16,370 letters archived, 30,100 total estimated to have been written ("Bahá'í Archives: Preserving and Safeguarding the Sacred Texts," in 'Andalíb magazine, 12.48 (Fall 1993): insert). William Collins has described the structure of the International Bahá'í Archives and other considerations relevant to preserving the sacred texts in "Library and Archival Resources at the Bahá'í World Centre," in Bahá'í Studies Bulletin, 3.4 (Dec. 1985).
Notes by Robert Stockman:
Bahá'u'lláh revealed over 15,000 tablets. Some are long (several hundred pages) but most are a page or two, written to a specific individual to answer a question or convey encouragement. Shoghi Effendi translated about a thousand pages into English in His lifetime.
Gleanings contains 166 extracts,
Prayers and Meditations 184, but some tablets provided more than one extract, so the total number of tablets that the Guardian used was less than the sum of the extracts in the two books (350). Since the Guardian did not assemble a list of his sources, it has been necessary to search for the original tablets he used, and they have not all been identified yet. More recently, the Universal House of Justice has overseen production of
Tablets of Bahá'u'lláh Revealed after the Kitáb-i-Aqdas and
The Kitáb-i-Aqdas: The Most Holy Book, rendering into English 500 more pages of revelation. It appears that less than 500 of the 15,000 tablets — a relatively small percentage of the total revelation — have been partially translated and published in English. Since the works were selected by the Guardian and Universal House of Justice, we can be sure that those available are the most significant and useful texts. Much of the rest probably is encouragement to individuals. We can also be sure that in subsequent centuries our understanding of the revelation of Bahá'u'lláh will undergo significant expansion and deepening as more tablets are translated.
A search for references to all the tablets discussed in English and Persian by Bahá'í writers shows that only about 360 tablets have names. In some cases the names were given by Bahá'u'lláh Himself (like the Hidden Words), `Abdu'l-Bahá, or Shoghi Effendi. In other cases the name is derived from a prominent theme (such as the Tablet to the Christians). Many tablets are named for their recipients (like the Tablet to Queen Victoria) but some individuals (like Salmán) received dozens of tablets and thus naming the tablets for their recipients can be confusing. A few tablets (such as the Lawh-i-Ra'ís [Adrianople period] and the Súriy-i-Ra'ís [early Akká period] are perpetually confused, and even Shoghi Effendi appears to use the two names interchangeably.
Taherzadeh's four-volume
Revelation of Bahá'u'lláh provides historical information on and summaries of only about 86 tablets. At least one prominent tablet is absent: the Kitáb-i-`Ahd, presumably because its date of revelation is unknown (and Taherzadeh's survey covers the revelation chronologically).
Number of tablets revealed by Bahá'u'lláh