Yishtabach is the concluding blessing of the Pesukei Dezmira – the Chapters/Verses of Praise that we recite each morning before Shema and the Amidah. The reason the blessing of Yishtabach does not contain the prescribed Talmudic formula of Baruch Atoh HaShem Elokeinu Melech Haolam is because it is a Bracha Hasemucha Lechavertah –A blessing that is connected to another one. The blessing of Yishtabach is halachically connected to Baruch Sheamar , the introductory blessing of Pesukei Dezimra, which does contain the full Talmudic formula. This same system is used after Yishtabach with a full formula for Yotzair Ohr Uvoray Choshech, and then abbreviated blessings for Yotzair Hameorot, Habochair Beomo Yisrael Beahava and Ga-al Yisrael. The system is also utilized during the recitation of Hallel and Birkat Hatorah, as well as in other places throughout our liturgy. Rav Yaakov Emden, in his Siddur Beit Yaakov, demonstrates that the first letter of the second to fifth words of Yishtabach spells Shlomo-Shimcha La-ad Malkeinu HaE-L which may indicate that the author of Yishtabach is King Solomon-Shlomo Hamelech. The Maharal explains the significance of the fifteen adulations of G-d starting from Shir Ushevacha ..until Brachot Vehodaot. He writes that it symbolizes the ascending of fifteen spiritual steps, which resembles the fifteen steps from the Ezrat Nashim – Women’s Corridor to the Ezrat Yisrael – Israelite Corridor in the Holy Temple, which in turn, reflects the fifteen different chapters of Shir Hamaalot – A Song of Ascents in Tehillim/Psalms (120-134) and the fifteen days from the beginning of the lunar month when the image of the moon gets larger and brighter each night until the fifteenth of the month. Why fifteen? Because it is the number that corresponds to G-d’s Name – Yud Heh=15, which the Talmud teaches are the letters G-d used to create our world and the World to Come (as it states in Isaiah 26:4 “Ki Bekah Hashem Tzur Olamim”). Since Yishtabach concludes “Melech E-l Chay Haolamim,” “King and Life source of all worlds,” it is ever so fitting that there are specifically fifteen praises recited. Finally, Rav Shimon Schwab zt”l, in his book On Prayer (pp 247), relates that the entire order of the Siddur reflects a walkthrough of the Beit Hamikdash –The Holy Temple. It begins with the prayers of Mah Tovu and Adon Olam outside the Ezrat Nashim – Women’s Corridor, and climaxes in the Kodesh Kadashim-Holy of Holies when we recite the Amidah. He explains that when we recite the Yishtabach, we are passing from the Ulam – antichamber to the Heichal – sanctuary where we could see the three great vessels, the Shulchan/Table on the right, the Menorah/Candelabra on the left and the Mizbayach Hazahav/The Golden Altar in the middle. Rav Schwab writes that we can see an allusion to these three great vessels through the three-time usage of the phrase E-l Melech. It says, HaE-l Hamelech Hagadol Vehakadosh, E-l Melech Gadol Batishbachot, Melech E-l Chay Haolamim. As we conclude Yishtabach and then hear Kaddish and recite Barchu, we are now ready to advance toward the blessings that precede Shema and recite the Shema itself.